{ "mode": "man", "parameter": "lvconvert", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvconvert/8/json", "generated": "2026-09-06T09:55:51Z", "synopsis": "lvconvert optionargs positionargs\n[ optionargs ]\n[ positionargs ]\n--alloc contiguous|cling|clingbytags|normal|anywhere|inherit\n-b|--background\n-H|--cache\n--cachedevice PV\n--cachemetadataformat auto|1|2\n--cachemode writethrough|writeback|passthrough\n--cachepolicy String\n--cachepool LV\n--cachesettings String\n--cachesize Size[m|UNIT]\n--cachevol LV\n-c|--chunksize Size[k|UNIT]\n--commandprofile String\n--compression y|n\n--config String\n-d|--debug\n--deduplication y|n\n--devices PV\n--devicesfile String\n--discards passdown|nopassdown|ignore\n--driverloaded y|n\n--errorwhenfull y|n\n-f|--force\n-h|--help\n-i|--interval Number\n--journal String\n--lockopt String\n--longhelp\n--merge\n--mergemirrors\n--mergesnapshot\n--mergethin\n--metadataprofile String\n--mirrorlog core|disk\n-m|--mirrors [+|-]Number\n-n|--name String\n--nohints\n--nolocking\n--noudevsync\n--originname LV\n--poolmetadata LV\n--poolmetadatasize Size[m|UNIT]\n--poolmetadataspare y|n\n--profile String\n-q|--quiet\n--raidintegrity y|n\n--raidintegrityblocksize Number\n--raidintegritymode String\n-r|--readahead auto|none|Number\n-R|--regionsize Size[m|UNIT]\n--repair\n--replace PV\n-s|--snapshot\n--splitcache\n--splitmirrors Number\n--splitsnapshot\n--startpoll\n--stripes Number\n-I|--stripesize Size[k|UNIT]\n--swapmetadata\n-t|--test\n-T|--thin\n--thinpool LV\n--trackchanges\n--type linear|striped|snapshot|raid|mirror|thin|thin-pool|vdo|vdo-pool|cache|cache-pool|", "sections": { "NAME": { "content": "lvconvert — Change logical volume layout\n", "subsections": [] }, "SYNOPSIS": { "content": "lvconvert optionargs positionargs\n[ optionargs ]\n[ positionargs ]\n\n--alloc contiguous|cling|clingbytags|normal|anywhere|inherit\n-b|--background\n-H|--cache\n--cachedevice PV\n--cachemetadataformat auto|1|2\n--cachemode writethrough|writeback|passthrough\n--cachepolicy String\n--cachepool LV\n--cachesettings String\n--cachesize Size[m|UNIT]\n--cachevol LV\n-c|--chunksize Size[k|UNIT]\n--commandprofile String\n--compression y|n\n--config String\n-d|--debug\n--deduplication y|n\n--devices PV\n--devicesfile String\n--discards passdown|nopassdown|ignore\n--driverloaded y|n\n--errorwhenfull y|n\n-f|--force\n-h|--help\n-i|--interval Number\n--journal String\n--lockopt String\n--longhelp\n--merge\n--mergemirrors\n--mergesnapshot\n--mergethin\n--metadataprofile String\n--mirrorlog core|disk\n-m|--mirrors [+|-]Number\n-n|--name String\n--nohints\n--nolocking\n--noudevsync\n--originname LV\n--poolmetadata LV\n--poolmetadatasize Size[m|UNIT]\n--poolmetadataspare y|n\n--profile String\n-q|--quiet\n--raidintegrity y|n\n--raidintegrityblocksize Number\n--raidintegritymode String\n-r|--readahead auto|none|Number\n-R|--regionsize Size[m|UNIT]\n--repair\n--replace PV\n-s|--snapshot\n--splitcache\n--splitmirrors Number\n--splitsnapshot\n--startpoll\n--stripes Number\n-I|--stripesize Size[k|UNIT]\n--swapmetadata\n-t|--test\n-T|--thin\n--thinpool LV\n--trackchanges\n--type linear|striped|snapshot|raid|mirror|thin|thin-pool|vdo|vdo-pool|cache|cache-pool|", "subsections": [ { "name": "writecache", "content": "--uncache\n--usepolicies\n--vdopool LV\n--vdosettings String\n-v|--verbose\n--version\n-V|--virtualsize Size[m|UNIT]\n-y|--yes\n-Z|--zero y|n\n" } ] }, "DESCRIPTION": { "content": "lvconvert changes the LV type and includes utilities for LV data maintenance. The LV type\ncontrols data layout and redundancy. The LV type is also called the segment type or segtype.\n\nTo display the current LV type, run the command:\n\nlvs -o name,segtype LV\n\nIn some cases, an LV is a single device mapper (dm) layer above physical devices. In other\ncases, hidden LVs (dm devices) are layered between the visible LV and physical devices. LVs\nin the middle layers are called sub LVs. A command run on a visible LV sometimes operates on\na sub LV rather than the specified LV. In other cases, a sub LV must be specified directly\non the command line.\n\nSub LVs can be displayed with the command:\n", "subsections": [ { "name": "lvs -a", "content": "The linear type is equivalent to the striped type when one stripe exists. In that case, the\ntypes can sometimes be used interchangably.\n\nIn most cases, the mirror type is deprecated and the raid1 type should be used. They are\nboth implementations of mirroring.\n\nStriped raid types are raid0/raid0meta, raid5 (an alias for raid5ls), raid6 (an alias for\nraid6zr) and raid10 (an alias for raid10near).\n\nAs opposed to mirroring, raid5 and raid6 stripe data and calculate parity blocks. The parity\nblocks can be used for data block recovery in case devices fail. A maximum number of one de‐\nvice in a raid5 LV may fail, and two in case of raid6. Striped raid types typically rotate\nthe parity and data blocks for performance reasons, thus avoiding contention on a single de‐\nvice. Specific arrangements of parity and data blocks (layouts) can be used to optimize I/O\nperformance, or to convert between raid levels. See lvmraid(7) for more information.\n\nLayouts of raid5 rotating parity blocks can be: left-asymmetric (raid5la), left-symmetric\n(raid5ls with alias raid5), right-asymmetric (raid5ra), right-symmetric (raid5rs) and\nraid5n, which doesn't rotate parity blocks. Layouts of raid6 are: zero-restart (raid6zr\nwith alias raid6), next-restart (raid6nr), and next-continue (raid6nc).\n\nLayouts including n allow for conversion between raid levels (raid5n to raid6 or raid5n to\nstriped/raid0/raid0meta). Additionally, special raid6 layouts for raid level conversions be‐\ntween raid5 and raid6 are: raid6ls6, raid6rs6, raid6la6 and raid6ra6. Those corre‐\nspond to their raid5 counterparts (e.g. raid5rs can be directly converted to raid6rs6 and\nvice-versa).\n\nraid10 (an alias for raid10near) is currently limited to one data copy and even number of\nsub LVs. This is a mirror group layout, thus a single sub LV may fail per mirror group with‐\nout data loss.\n\nStriped raid types support converting the layout, their stripesize and their number of\nstripes.\n\nThe striped raid types combined with raid1 allow for conversion from linear →\nstriped/raid0/raid0meta and vice-versa by e.g. linear ↔ raid1 ↔ raid5n (then adding\nstripes) ↔ striped/raid0/raid0meta.\n" } ] }, "USAGE": { "content": "Convert LV to linear.\n\nlvconvert --type linear LV\n[ COMMONOPTIONS ]\n[ PV ... ]\n\n—\n\nConvert LV to striped.\n\nlvconvert --type striped LV\n[ -I|--stripesize Size[k|UNIT] ]\n[ -R|--regionsize Size[m|UNIT] ]\n[ -i|--interval Number ]\n[ --stripes Number ]\n[ COMMONOPTIONS ]\n[ PV ... ]\n\n—\n\nConvert LV to type mirror (also see type raid1),\n\nlvconvert --type mirror LV\n[ -m|--mirrors [+|-]Number ]\n[ -I|--stripesize Size[k|UNIT] ]\n[ -R|--regionsize Size[m|UNIT] ]\n[ -i|--interval Number ]\n[ --stripes Number ]\n[ --mirrorlog core|disk ]\n[ COMMONOPTIONS ]\n[ PV ... ]\n\n—\n\nConvert LV to raid or change raid layout\n(a specific raid level must be used, e.g. raid1).\n\nlvconvert --type raid LV\n[ -m|--mirrors [+|-]Number ]\n[ -I|--stripesize Size[k|UNIT] ]\n[ -R|--regionsize Size[m|UNIT] ]\n[ -i|--interval Number ]\n[ --stripes Number ]\n[ COMMONOPTIONS ]\n[ PV ... ]\n\n—\n\nConvert LV to raid1 or mirror, or change number of mirror images.\n\nlvconvert -m|--mirrors [+|-]Number LV\n[ -R|--regionsize Size[m|UNIT] ]\n[ -i|--interval Number ]\n[ --mirrorlog core|disk ]\n[ COMMONOPTIONS ]\n[ PV ... ]\n\n—\n\nConvert raid LV to change number of stripe images.\n\nlvconvert --stripes Number LV1\n[ -i|--interval Number ]\n[ -R|--regionsize Size[m|UNIT] ]\n[ -I|--stripesize Size[k|UNIT] ]\n[ COMMONOPTIONS ]\n[ PV ... ]\n\nLV1 types: raid\n\n—\n\nConvert raid LV to change the stripe size.\n\nlvconvert -I|--stripesize Size[k|UNIT] LV1\n[ -i|--interval Number ]\n[ -R|--regionsize Size[m|UNIT] ]\n[ COMMONOPTIONS ]\n\nLV1 types: raid\n\n—\n\nSplit images from a raid1 or mirror LV and use them to create a new LV.\n\nlvconvert --splitmirrors Number -n|--name LVnew LV1\n[ COMMONOPTIONS ]\n[ PV ... ]\n\nLV1 types: cache mirror raid1\n\n—\n\nSplit images from a raid1 LV and track changes to origin for later merge.\n\nlvconvert --splitmirrors Number --trackchanges LV1\n[ COMMONOPTIONS ]\n[ PV ... ]\n\nLV1 types: cache raid1\n\n—\n\nMerge LV images that were split from a raid1 LV.\n\nlvconvert --mergemirrors VG|LV1|Tag ...\n[ COMMONOPTIONS ]\n\nLV1 types: linear raid\n\n—\n\nConvert LV to a thin LV, using the original LV as an external origin.\n\nlvconvert --type thin --thinpool LV LV1\n[ -T|--thin ]\n[ -r|--readahead auto|none|Number ]\n[ -c|--chunksize Size[k|UNIT] ]\n[ -Z|--zero y|n ]\n[ --originname LVnew ]\n[ --poolmetadata LV ]\n[ --poolmetadatasize Size[m|UNIT] ]\n[ --poolmetadataspare y|n ]\n[ --metadataprofile String ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped thin cache raid error zero\n\n—\n\nAttach a cache pool to an LV, converts the LV to type cache.\n\nlvconvert --type cache --cachepool LV LV1\n[ -H|--cache ]\n[ -Z|--zero y|n ]\n[ -r|--readahead auto|none|Number ]\n[ -c|--chunksize Size[k|UNIT] ]\n[ --cachemetadataformat auto|1|2 ]\n[ --cachemode writethrough|writeback|passthrough ]\n[ --cachepolicy String ]\n[ --cachesettings String ]\n[ --poolmetadata LV ]\n[ --poolmetadatasize Size[m|UNIT] ]\n[ --poolmetadataspare y|n ]\n[ --metadataprofile String ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped thinpool vdo vdopool vdopooldata raid\n\n—\n\nAttach a writecache to an LV, converts the LV to type writecache.\n\nlvconvert --type writecache --cachevol LV LV1\n[ --cachesettings String ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped thinpool raid\n\n—\n\nAttach a cache to an LV, converts the LV to type cache.\n\nlvconvert --type cache --cachevol LV LV1\n[ -H|--cache ]\n[ -Z|--zero y|n ]\n[ -c|--chunksize Size[k|UNIT] ]\n[ --cachemetadataformat auto|1|2 ]\n[ --cachemode writethrough|writeback|passthrough ]\n[ --cachepolicy String ]\n[ --cachesettings String ]\n[ --poolmetadatasize Size[m|UNIT] ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped thinpool raid\n\n—\n\nAdd a writecache to an LV, using a specified cache device.\n\nlvconvert --type writecache --cachedevice PV LV1\n[ --cachesize Size[m|UNIT] ]\n[ --cachesettings String ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped thinpool raid\n\n—\n\nAdd a cache to an LV, using a specified cache device.\n\nlvconvert --type cache --cachedevice PV LV1\n[ -c|--chunksize Size[k|UNIT] ]\n[ --cachesize Size[m|UNIT] ]\n[ --cachesettings String ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped thinpool raid\n\n—\n\nConvert LV to type thin-pool.\n\nlvconvert --type thin-pool LV1\n[ -I|--stripesize Size[k|UNIT] ]\n[ -r|--readahead auto|none|Number ]\n[ -c|--chunksize Size[k|UNIT] ]\n[ -Z|--zero y|n ]\n[ --stripes Number ]\n[ --discards passdown|nopassdown|ignore ]\n[ --errorwhenfull y|n ]\n[ --poolmetadata LV ]\n[ --poolmetadatasize Size[m|UNIT] ]\n[ --poolmetadataspare y|n ]\n[ --metadataprofile String ]\n[ COMMONOPTIONS ]\n[ PV ... ]\n\nLV1 types: linear striped cache raid error zero writecache\n\n—\n\nConvert LV to type cache-pool.\n\nlvconvert --type cache-pool LV1\n[ -Z|--zero y|n ]\n[ -r|--readahead auto|none|Number ]\n[ -c|--chunksize Size[k|UNIT] ]\n[ --cachemetadataformat auto|1|2 ]\n[ --cachemode writethrough|writeback|passthrough ]\n[ --cachepolicy String ]\n[ --cachesettings String ]\n[ --poolmetadata LV ]\n[ --poolmetadatasize Size[m|UNIT] ]\n[ --poolmetadataspare y|n ]\n[ --metadataprofile String ]\n[ COMMONOPTIONS ]\n[ PV ... ]\n\nLV1 types: linear striped raid\n\n—\n\nConvert LV to type vdopool.\n\nlvconvert --type vdo-pool LV1\n[ -n|--name LVnew ]\n[ -V|--virtualsize Size[m|UNIT] ]\n[ -r|--readahead auto|none|Number ]\n[ -Z|--zero y|n ]\n[ --metadataprofile String ]\n[ --compression y|n ]\n[ --deduplication y|n ]\n[ --vdosettings String ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped cache raid\n\n—\n\nDetach a cache from an LV.\n\nlvconvert --splitcache LV1\n[ --cachesettings String ]\n[ COMMONOPTIONS ]\n\nLV1 types: thinpool cache cachepool vdopool writecache\n\n—\n\nMerge thin LV into its origin LV.\n\nlvconvert --mergethin LV1 ...\n[ COMMONOPTIONS ]\n\nLV1 types: thin\n\n—\n\nMerge COW snapshot LV into its origin.\n\nlvconvert --mergesnapshot LV1 ...\n[ -i|--interval Number ]\n[ COMMONOPTIONS ]\n\nLV1 types: snapshot\n\n—\n\nCombine a former COW snapshot (second arg) with a former\norigin LV (first arg) to reverse a splitsnapshot command.\n\nlvconvert --type snapshot LV LV1\n[ -s|--snapshot ]\n[ -c|--chunksize Size[k|UNIT] ]\n[ -Z|--zero y|n ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped\n\n—\n\nReplace failed PVs in a raid or mirror LV.\nRepair a thin pool.\nRepair a cache pool.\n\nlvconvert --repair LV1\n[ -i|--interval Number ]\n[ --usepolicies ]\n[ --poolmetadataspare y|n ]\n[ COMMONOPTIONS ]\n[ PV ... ]\n\nLV1 types: thinpool cache cachepool mirror raid\n\n—\n\nReplace specific PV(s) in a raid LV with another PV.\n\nlvconvert --replace PV LV1\n[ COMMONOPTIONS ]\n[ PV ... ]\n\nLV1 types: raid\n\n—\n\nPoll LV to continue conversion.\n\nlvconvert --startpoll LV1\n[ COMMONOPTIONS ]\n\nLV1 types: mirror raid\n\n—\n\nAdd or remove data integrity checksums to raid images.\n\nlvconvert --raidintegrity y|n LV1\n[ --raidintegritymode String ]\n[ --raidintegrityblocksize Number ]\n[ COMMONOPTIONS ]\n[ PV ... ]\n\nLV1 types: raid\n\n—\n\nCommon options for command:\n[ -b|--background ]\n[ -f|--force ]\n[ --alloc contiguous|cling|clingbytags|normal|anywhere|inherit ]\n[ --noudevsync ]\n\nCommon options for lvm:\n[ -d|--debug ]\n[ -h|--help ]\n[ -q|--quiet ]\n[ -t|--test ]\n[ -v|--verbose ]\n[ -y|--yes ]\n[ --commandprofile String ]\n[ --config String ]\n[ --devices PV ]\n[ --devicesfile String ]\n[ --driverloaded y|n ]\n[ --journal String ]\n[ --lockopt String ]\n[ --longhelp ]\n[ --nohints ]\n[ --nolocking ]\n[ --profile String ]\n[ --version ]\n", "subsections": [] }, "OPTIONS": { "content": "--alloc contiguous|cling|clingbytags|normal|anywhere|inherit\nDetermines the allocation policy when a command needs to allocate Physical Extents\n(PEs) from the VG. Each VG and LV has an allocation policy which can be changed with\nvgchange/lvchange, or overridden on the command line. normal applies common sense\nrules such as not placing parallel stripes on the same PV. inherit applies the VG\npolicy to an LV. contiguous requires new PEs be placed adjacent to existing PEs.\ncling places new PEs on the same PV as existing PEs in the same stripe of the LV. If\nthere are sufficient PEs for an allocation, but normal does not use them, anywhere\nwill use them even if it reduces performance, e.g. by placing two stripes on the same\nPV. Optional positional PV args on the command line can also be used to limit which\nPVs the command will use for allocation. See lvm(8) for more information about allo‐\ncation.\n", "subsections": [ { "name": "-b --background", "content": "If the operation requires polling, this option causes the command to return before the\noperation is complete, and polling is done in the background.\n", "flag": "-b", "long": "--background" }, { "name": "-H --cache", "content": "Specifies the command is handling a cache LV or cache pool. See --type cache and\n--type cache-pool. See lvmcache(7) for more information about LVM caching.\n\n--cachedevice PV\nThe name of a device to use for a cache.\n\n--cachemetadataformat auto|1|2\nSpecifies the cache metadata format used by cache target.\n\n--cachemode writethrough|writeback|passthrough\nSpecifies when writes to a cache LV should be considered complete. writeback consid‐\ners a write complete as soon as it is stored in the cache pool. writethough considers\na write complete only when it has been stored in both the cache pool and on the origin\nLV. While writethrough may be slower for writes, it is more resilient if something\nshould happen to a device associated with the cache pool LV. With passthrough, all\nreads are served from the origin LV (all reads miss the cache) and all writes are for‐\nwarded to the origin LV; additionally, write hits cause cache block invalidates. See\nlvmcache(7) for more information.\n\n--cachepolicy String\nSpecifies the cache policy for a cache LV. See lvmcache(7) for more information.\n\n--cachepool LV\nThe name of a cache pool.\n\n--cachesettings String\nSpecifies tunable kernel options for dm-cache or dm-writecache LVs. Use the form 'op‐\ntion=value' or 'option1=value option2=value', or repeat --cachesettings for each op‐\ntion being set. These settings override the default kernel behaviors which are usual‐\nly adequate. To remove cachesettings and revert to the default kernel behaviors, use\n--cachesettings 'default' for dm-cache or an empty string --cachesettings '' for dm-\nwritecache. See lvmcache(7) for more information.\n\n--cachesize Size[m|UNIT]\nThe size of cache to use.\n\n--cachevol LV\nThe name of a cache volume.\n", "flag": "-H", "long": "--cache" }, { "name": "-c --chunksize _", "content": "The size of chunks in a snapshot, cache pool or thin pool. For snapshots, the value\nmust be a power of 2 between 4KiB and 512KiB and the default value is 4. For a cache\npool the value must be between 32KiB and 1GiB and the default value is 64. For a thin\npool the value must be between 64KiB and 1GiB and the default value starts with 64 and\nscales up to fit the pool metadata size within 128MiB, if the pool metadata size is\nnot specified. The value must be a multiple of 64KiB. See lvmthin(7) and lvmcache(7)\nfor more information.\n\n--commandprofile String\nThe command profile to use for command configuration. See lvm.conf(5) for more infor‐\nmation about profiles.\n\n--compression y|n\nControls whether compression is enabled or disable for VDO volume. See lvmvdo(7) for\nmore information about VDO usage.\n\n--config String\nConfig settings for the command. These override lvm.conf(5) settings. The String arg\nuses the same format as lvm.conf(5), or may use section/field syntax. See lvm.conf(5)\nfor more information about config.\n", "flag": "-c", "long": "--chunksize" }, { "name": "-d --debug", "content": "Set debug level. Repeat from 1 to 6 times to increase the detail of messages sent to\nthe log file and/or syslog (if configured).\n\n--deduplication y|n\nControls whether deduplication is enabled or disable for VDO volume. See lvmvdo(7)\nfor more information about VDO usage.\n\n--devices PV\nRestricts the devices that are visible and accessible to the command. Devices not\nlisted will appear to be missing. This option can be repeated, or accepts a comma sep‐\narated list of devices. This overrides the devices file.\n\n--devicesfile String\nA file listing devices that LVM should use. The file must exist in /etc/lvm/devices/\nand is managed with the lvmdevices(8) command. This overrides the lvm.conf(5) de‐\nvices/devicesfile and devices/usedevicesfile settings.\n\n--discards passdown|nopassdown|ignore\nSpecifies how the device-mapper thin pool layer in the kernel should handle discards.\nignore causes the thin pool to ignore discards. nopassdown causes the thin pool to\nprocess discards itself to allow reuse of unneeded extents in the thin pool. passdown\ncauses the thin pool to process discards itself (like nopassdown) and pass the dis‐\ncards to the underlying device. See lvmthin(7) for more information.\n\n--driverloaded y|n\nIf set to no, the command will not attempt to use device-mapper. For testing and de‐\nbugging.\n\n--errorwhenfull y|n\nSpecifies thin pool behavior when data space is exhausted. When yes, device-mapper\nwill immediately return an error when a thin pool is full and an I/O request requires\nspace. When no, device-mapper will queue these I/O requests for a period of time to\nallow the thin pool to be extended. Errors are returned if no space is available af‐\nter the timeout. (Also see dm-thin-pool kernel module option nospacetimeout.) See\nlvmthin(7) for more information.\n", "flag": "-d", "long": "--debug" }, { "name": "-f --force", "content": "Override various checks, confirmations and protections. Use with extreme caution.\n", "flag": "-f", "long": "--force" }, { "name": "-h --help", "content": "Display help text.\n", "flag": "-h", "long": "--help" }, { "name": "-i --interval _", "content": "Report progress at regular intervals.\n\n--journal String\nRecord information in the systemd journal. This information is in addition to infor‐\nmation enabled by the lvm.conf log/journal setting. command: record information about\nthe command. output: record the default command output. debug: record full command\ndebugging.\n\n--lockopt String\nUsed to pass options for special cases to lvmlockd. See lvmlockd(8) for more informa‐\ntion.\n", "flag": "-i", "long": "--interval" }, { "name": "--longhelp", "content": "Display long help text.\n", "long": "--longhelp" }, { "name": "--merge", "content": "An alias for --mergethin, --mergemirrors, or --mergesnapshot, depending on the type of\nLV.\n", "long": "--merge" }, { "name": "--mergemirrors", "content": "Merge LV images that were split from a raid1 LV. See --splitmirrors with\n--trackchanges.\n", "long": "--mergemirrors" }, { "name": "--mergesnapshot", "content": "Merge COW snapshot LV into its origin. When merging a snapshot, if both the origin\nand snapshot LVs are not open, the merge will start immediately. Otherwise, the merge\nwill start the first time either the origin or snapshot LV are activated and both are\nclosed. Merging a snapshot into an origin that cannot be closed, for example a root\nfilesystem, is deferred until the next time the origin volume is activated. When merg‐\ning starts, the resulting LV will have the origin's name, minor number and UUID. While\nthe merge is in progress, reads or writes to the origin appear as being directed to\nthe snapshot being merged. When the merge finishes, the merged snapshot is removed.\nMultiple snapshots may be specified on the command line or a @tag may be used to spec‐\nify multiple snapshots be merged to their respective origin.\n", "long": "--mergesnapshot" }, { "name": "--mergethin", "content": "Merge thin LV into its origin LV. The origin thin LV takes the content of the thin\nsnapshot, and the thin snapshot LV is removed. See lvmthin(7) for more information.\n\n--metadataprofile String\nThe metadata profile to use for command configuration. See lvm.conf(5) for more in‐\nformation about profiles.\n\n--mirrorlog core|disk\nSpecifies the type of mirror log for LVs with the \"mirror\" type (does not apply to the\n\"raid1\" type.) disk is a persistent log and requires a small amount of storage space,\nusually on a separate device from the data being mirrored. core is not persistent;\nthe log is kept only in memory. In this case, the mirror must be synchronized (by\ncopying LV data from the first device to others) each time the LV is activated, e.g.\nafter reboot. mirrored is a persistent log that is itself mirrored, but should be\navoided. Instead, use the raid1 type for log redundancy.\n", "long": "--mergethin" }, { "name": "-m --mirrors -", "content": "Specifies the number of mirror images in addition to the original LV image, e.g.\n--mirrors 1 means there are two images of the data, the original and one mirror image.\nOptional positional PV args on the command line can specify the devices the images\nshould be placed on. There are two mirroring implementations: \"raid1\" and \"mirror\".\nThese are the names of the corresponding LV types, or \"segment types\". Use the --type\noption to specify which to use (raid1 is default, and mirror is legacy) Use\nlvm.conf(5) global/mirrorsegtypedefault and global/raid10segtypedefault to config‐\nure the default types. The plus prefix + can be used, in which case the number is\nadded to the current number of images, or the minus prefix - can be used, in which\ncase the number is subtracted from the current number of images. See lvmraid(7) for\nmore information.\n", "flag": "-m", "long": "--mirrors" }, { "name": "-n --name _", "content": "Specifies the name of a new LV. When unspecified, a default name of \"lvol#\" is gener‐\nated, where # is a number generated by LVM.\n", "flag": "-n", "long": "--name" }, { "name": "--nohints", "content": "Do not use the hints file to locate devices for PVs. A command may read more devices\nto find PVs when hints are not used. The command will still perform standard hint file\ninvalidation where appropriate.\n", "long": "--nohints" }, { "name": "--nolocking", "content": "Disable locking. Use with caution, concurrent commands may produce incorrect results.\n\n", "long": "--nolocking" }, { "name": "--noudevsync", "content": "Disables udev synchronisation. The process will not wait for notification from udev.\nIt will continue irrespective of any possible udev processing in the background. Only\nuse this if udev is not running or has rules that ignore the devices LVM creates.\n\n--originname LV\nSpecifies the name to use for the external origin LV when converting an LV to a thin\nLV. The LV being converted becomes a read-only external origin with this name.\n\n--poolmetadata LV\nThe name of a an LV to use for storing pool metadata.\n\n--poolmetadatasize Size[m|UNIT]\nSpecifies the size of the new pool metadata LV.\n\n--poolmetadataspare y|n\nEnable or disable the automatic creation and management of a spare pool metadata LV in\nthe VG. A spare metadata LV is reserved space that can be used when repairing a pool.\n\n\n--profile String\nAn alias for --commandprofile or --metadataprofile, depending on the command.\n", "long": "--noudevsync" }, { "name": "-q --quiet", "content": "Suppress output and log messages. Overrides --debug and --verbose. Repeat once to al‐\nso suppress any prompts with answer 'no'.\n\n--raidintegrity y|n\nEnable or disable data integrity checksums for raid images.\n\n--raidintegrityblocksize Number\nThe block size to use for dm-integrity on raid images. The integrity block size\nshould usually match the device logical block size, or the file system block size. It\nmay be less than the file system block size, but not less than the device logical\nblock size. Possible values: 512, 1024, 2048, 4096.\n\n--raidintegritymode String\nUse a journal (default) or bitmap for keeping integrity checksums consistent in case\nof a crash. The bitmap areas are recalculated after a crash, so corruption in those\nareas would not be detected. A journal does not have this problem. The journal mode\ndoubles writes to storage, but can improve performance for scattered writes packed in‐\nto a single journal write. bitmap mode can in theory achieve full write throughput of\nthe device, but would not benefit from the potential scattered write optimization.\n", "flag": "-q", "long": "--quiet" }, { "name": "-r --readahead auto", "content": "Sets read ahead sector count of an LV. auto is the default which allows the kernel to\nchoose a suitable value automatically. none is equivalent to zero.\n", "flag": "-r", "long": "--readahead" }, { "name": "-R --regionsize _", "content": "Size of each raid or mirror synchronization region. lvm.conf(5) activation/raidre‐\ngionsize can be used to configure a default.\n", "flag": "-R", "long": "--regionsize" }, { "name": "--repair", "content": "Replace failed PVs in a raid or mirror LV, or run a repair utility on a thin pool. See\nlvmraid(7) and lvmthin(7) for more information.\n\n--replace PV\nReplace a specific PV in a raid LV with another PV. The new PV to use can be option‐\nally specified after the LV. Multiple PVs can be replaced by repeating this option.\nSee lvmraid(7) for more information.\n", "long": "--repair" }, { "name": "-s --snapshot", "content": "Combine a former COW snapshot LV with a former origin LV to reverse a previous\n--splitsnapshot command.\n", "flag": "-s", "long": "--snapshot" }, { "name": "--splitcache", "content": "Separates a cache pool from a cache LV, and keeps the unused cache pool LV. Before\nthe separation, the cache is flushed. Also see --uncache.\n\n--splitmirrors Number\nSplits the specified number of images from a raid1 or mirror LV and uses them to cre‐\nate a new LV. If --trackchanges is also specified, changes to the raid1 LV are tracked\nwhile the split LV remains detached. If --name is specified, then the images are per‐\nmanently split from the original LV and changes are not tracked.\n", "long": "--splitcache" }, { "name": "--splitsnapshot", "content": "Separates a COW snapshot from its origin LV. The LV that is split off contains the\nchunks that differ from the origin LV along with metadata describing them. This LV can\nbe wiped and then destroyed with lvremove.\n", "long": "--splitsnapshot" }, { "name": "--startpoll", "content": "Start polling an LV to continue processing a conversion.\n\n--stripes Number\nSpecifies the number of stripes in a striped LV. This is the number of PVs (devices)\nthat a striped LV is spread across. Data that appears sequential in the LV is spread\nacross multiple devices in units of the stripe size (see --stripesize). This does not\napply to existing allocated space, only newly allocated space can be striped.\n", "long": "--startpoll" }, { "name": "-I --stripesize _", "content": "The amount of data that is written to one device before moving to the next in a\nstriped LV.\n", "flag": "-I", "long": "--stripesize" }, { "name": "--swapmetadata", "content": "Extracts the metadata LV from a pool and replaces it with another specified LV. The\nextracted LV is preserved and given the name of the LV that replaced it. Use for re‐\npair only. When the metadata LV is swapped out of the pool, it can be activated di‐\nrectly and used with thin provisioning tools: cachedump(8), cacherepair(8),\ncacherestore(8), thindump(8), thinrepair(8), thinrestore(8).\n", "long": "--swapmetadata" }, { "name": "-t --test", "content": "Run in test mode. Commands will not update metadata. This is implemented by disabling\nall metadata writing but nevertheless returning success to the calling function. This\nmay lead to unusual error messages in multi-stage operations if a tool relies on read‐\ning back metadata it believes has changed but hasn't.\n", "flag": "-t", "long": "--test" }, { "name": "-T --thin", "content": "Specifies the command is handling a thin LV or thin pool. See --type thin, --type\nthin-pool, and --virtualsize. See lvmthin(7) for more information about LVM thin pro‐\nvisioning.\n\n--thinpool LV\nThe name of a thin pool LV.\n", "flag": "-T", "long": "--thin" }, { "name": "--trackchanges", "content": "Can be used with --splitmirrors on a raid1 LV. This causes changes to the original\nraid1 LV to be tracked while the split images remain detached. This is a temporary\nstate that allows the read-only detached image to be merged efficiently back into the\nraid1 LV later. Only the regions with changed data are resynchronized during merge.\nWhile a raid1 LV is tracking changes, operations on it are limited to merging the\nsplit image (see --mergemirrors) or permanently splitting the image (see --splitmir‐\nrors with --name.\n\n--type linear|striped|snapshot|raid|mirror|thin|thin-pool|vdo|vdo-pool|cache|cache-pool|\nwritecache\nThe LV type, also known as \"segment type\" or \"segtype\". See usage descriptions for\nthe specific ways to use these types. For more information about redundancy and per‐\nformance (raid, mirror, striped, linear) see lvmraid(7). For thin provisioning\n(thin, thin-pool) see lvmthin(7). For performance caching (cache, cache-pool) see\nlvmcache(7). For copy-on-write snapshots (snapshot) see usage definitions. For VDO\n(vdo) see lvmvdo(7). Several commands omit an explicit type option because the type\nis inferred from other options or shortcuts (e.g. --stripes, --mirrors, --snapshot,\n--virtualsize, --thin, --cache, --vdo). Use inferred types with care because it can\nlead to unexpected results.\n", "long": "--trackchanges" }, { "name": "--uncache", "content": "Separates a cache pool from a cache LV, and deletes the unused cache pool LV. Before\nthe separation, the cache is flushed. Also see --splitcache.\n", "long": "--uncache" }, { "name": "--usepolicies", "content": "Perform an operation according to the policy configured in lvm.conf(5) or a profile.\n\n--vdopool LV\nThe name of a VDO pool LV. See lvmvdo(7) for more information about VDO usage.\n\n--vdosettings String\nSpecifies tunable VDO options for VDO LVs. Use the form 'option=value' or 'op‐\ntion1=value option2=value', or repeat --vdosettings for each option being set. These\nsettings override the default VDO behaviors. To remove vdosettings and revert to the\ndefault VDO behaviors, use --vdosettings 'default'. See lvmvdo(7) for more informa‐\ntion.\n", "long": "--usepolicies" }, { "name": "-v --verbose", "content": "Set verbose level. Repeat from 1 to 4 times to increase the detail of messages sent to\nstdout and stderr.\n", "flag": "-v", "long": "--verbose" }, { "name": "--version", "content": "Display version information.\n", "long": "--version" }, { "name": "-V --virtualsize _", "content": "The virtual size of a new thin LV. See lvmthin(7) for more information about LVM thin\nprovisioning. Using virtual size (-V) and actual size (-L) together creates a sparse\nLV. lvm.conf(5) global/sparsesegtypedefault determines the default segment type\nused to create a sparse LV. Anything written to a sparse LV will be returned when\nreading from it. Reading from other areas of the LV will return blocks of zeros.\nWhen using a snapshot to create a sparse LV, a hidden virtual device is created using\nthe zero target, and the LV has the suffix vorigin. Snapshots are less efficient\nthan thin provisioning when creating large sparse LVs (GiB).\n", "flag": "-V", "long": "--virtualsize" }, { "name": "-y --yes", "content": "Do not prompt for confirmation interactively but always assume the answer yes. Use\nwith extreme caution. (For automatic no, see -qq.)\n", "flag": "-y", "long": "--yes" }, { "name": "-Z --zero y", "content": "For snapshots, this controls zeroing of the first 4KiB of data in the snapshot. If the\nLV is read-only, the snapshot will not be zeroed. For thin pools, this controls zero‐\ning of provisioned blocks. Provisioning of large zeroed chunks negatively impacts\nperformance.\n", "flag": "-Z", "long": "--zero" } ] }, "VARIABLES": { "content": "VG Volume Group name. See lvm(8) for valid names.\n\nLV Logical Volume name. See lvm(8) for valid names. An LV positional arg generally in‐\ncludes the VG name and LV name, e.g. VG/LV. LV1 indicates the LV must have a specific\ntype, where the accepted LV types are listed. (raid represents raid type).\n\nPV Physical Volume name, a device path under /dev. For commands managing physical ex‐\ntents, a PV positional arg generally accepts a suffix indicating a range (or multiple\nranges) of physical extents (PEs). When the first PE is omitted, it defaults to the\nstart of the device, and when the last PE is omitted it defaults to end. Start and\nend range (inclusive): PV[:PE-PE]... Start and length range (counting from 0):\nPV[:PE+PE]...\n\nTag Tag name. See lvm(8) for information about tag names and using tags in place of a VG,\nLV or PV.\n\nString See the option description for information about the string content.\n\nSize[UNIT]\nSize is an input number that accepts an optional unit. Input units are always treated\nas base two values, regardless of capitalization, e.g. 'k' and 'K' both refer to 1024.\nThe default input unit is specified by letter, followed by |UNIT. UNIT represents\nother possible input units: b|B is bytes, s|S is sectors of 512 bytes, k|K is KiB, m|M\nis MiB, g|G is GiB, t|T is TiB, p|P is PiB, e|E is EiB. (This should not be confused\nwith the output control --units, where capital letters mean multiple of 1000.)\n", "subsections": [] }, "ENVIRONMENT VARIABLES": { "content": "See lvm(8) for information about environment variables used by lvm. For example, LVMVGNAME\ncan generally be substituted for a required VG parameter.\n", "subsections": [] }, "ADVANCED USAGE": { "content": "Alternate command forms, advanced command usage, and listing of all valid syntax for com‐\npleteness.\n\nChange the region size of an LV.\n\nlvconvert -R|--regionsize Size[m|UNIT] LV1\n[ COMMONOPTIONS ]\n\nLV1 types: raid\n\n—\n\nChange the type of mirror log used by a mirror LV.\n\nlvconvert --mirrorlog core|disk LV1\n[ COMMONOPTIONS ]\n[ PV ... ]\n\nLV1 types: mirror\n\n—\n\nConvert LV to a thin LV, using the original LV as an external origin.\n\nlvconvert -T|--thin --thinpool LV LV1\n[ --type thin ] (implied)\n[ -r|--readahead auto|none|Number ]\n[ -c|--chunksize Size[k|UNIT] ]\n[ -Z|--zero y|n ]\n[ --originname LVnew ]\n[ --poolmetadata LV ]\n[ --poolmetadatasize Size[m|UNIT] ]\n[ --poolmetadataspare y|n ]\n[ --metadataprofile String ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped thin cache raid error zero\n\n—\n\nAttach a cache pool to an LV.\n\nlvconvert -H|--cache --cachepool LV LV1\n[ --type cache ] (implied)\n[ -Z|--zero y|n ]\n[ -r|--readahead auto|none|Number ]\n[ -c|--chunksize Size[k|UNIT] ]\n[ --cachemetadataformat auto|1|2 ]\n[ --cachemode writethrough|writeback|passthrough ]\n[ --cachepolicy String ]\n[ --cachesettings String ]\n[ --poolmetadata LV ]\n[ --poolmetadatasize Size[m|UNIT] ]\n[ --poolmetadataspare y|n ]\n[ --metadataprofile String ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped thinpool vdo vdopool vdopooldata raid\n\n—\n\nAttach a cache to an LV, converts the LV to type cache.\n\nlvconvert -H|--cache --cachevol LV LV1\n[ -Z|--zero y|n ]\n[ -c|--chunksize Size[k|UNIT] ]\n[ --cachemetadataformat auto|1|2 ]\n[ --cachemode writethrough|writeback|passthrough ]\n[ --cachepolicy String ]\n[ --cachesettings String ]\n[ --poolmetadatasize Size[m|UNIT] ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped thinpool raid\n\n—\n\nConvert LV to type vdopool.\n\nlvconvert --vdopool LV\n[ --type vdo-pool ] (implied)\n[ -r|--readahead auto|none|Number ]\n[ -Z|--zero y|n ]\n[ -n|--name LVnew ]\n[ -V|--virtualsize Size[m|UNIT] ]\n[ --metadataprofile String ]\n[ --compression y|n ]\n[ --deduplication y|n ]\n[ --vdosettings String ]\n[ COMMONOPTIONS ]\n\n—\n\nDetach and delete a cache from an LV.\n\nlvconvert --uncache LV1\n[ --cachesettings String ]\n[ COMMONOPTIONS ]\n\nLV1 types: thinpool cache vdopool writecache\n\n—\n\nSwap metadata LV in a thin pool or cache pool (for repair only).\n\nlvconvert --swapmetadata --poolmetadata LV LV1\n[ -c|--chunksize Size[k|UNIT] ]\n[ COMMONOPTIONS ]\n\nLV1 types: thinpool cachepool\n\n—\n\nMerge LV that was split from a mirror (variant, use --mergemirrors).\nMerge thin LV into its origin LV (variant, use --mergethin).\nMerge COW snapshot LV into its origin (variant, use --mergesnapshot).\n\nlvconvert --merge VG|LV1|Tag ...\n[ -i|--interval Number ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped snapshot thin raid\n\n—\n\nSeparate a COW snapshot from its origin LV.\n\nlvconvert --splitsnapshot LV1\n[ COMMONOPTIONS ]\n\nLV1 types: snapshot\n\n—\n\nCombine a former COW snapshot (second arg) with a former\norigin LV (first arg) to reverse a splitsnapshot command.\n\nlvconvert -s|--snapshot LV LV1\n[ --type snapshot ] (implied)\n[ -c|--chunksize Size[k|UNIT] ]\n[ -Z|--zero y|n ]\n[ COMMONOPTIONS ]\n\nLV1 types: linear striped\n\n—\n\nPoll LV to continue conversion (also see --startpoll)\nor waits till conversion/mirror syncing is finished\n\nlvconvert LV1\n[ COMMONOPTIONS ]\n\nLV1 types: mirror raid\n\n—\n", "subsections": [] }, "NOTES": { "content": "This previous command syntax would perform two different operations:\nlvconvert --thinpool LV1 --poolmetadata LV2\nIf LV1 was not a thin pool, the command would convert LV1 to a thin pool, optionally using a\nspecified LV for metadata. But, if LV1 was already a thin pool, the command would swap the\ncurrent metadata LV with LV2 (for repair purposes.)\n\nIn the same way, this previous command syntax would perform two different operations:\nlvconvert --cachepool LV1 --poolmetadata LV2\nIf LV1 was not a cache pool, the command would convert LV1 to a cache pool, optionally using\na specified LV for metadata. But, if LV1 was already a cache pool, the command would swap\nthe current metadata LV with LV2 (for repair purposes.)\n", "subsections": [] }, "EXAMPLES": { "content": "Convert a linear LV to a two-way mirror LV.", "subsections": [ { "name": "lvconvert --type mirror --mirrors 1 vg/lvol1", "content": "Convert a linear LV to a two-way RAID1 LV." }, { "name": "lvconvert --type raid1 --mirrors 1 vg/lvol1", "content": "Convert a mirror LV to use an in-memory log." }, { "name": "lvconvert --mirrorlog core vg/lvol1", "content": "Convert a mirror LV to use a disk log." }, { "name": "lvconvert --mirrorlog disk vg/lvol1", "content": "Convert a mirror or raid1 LV to a linear LV." }, { "name": "lvconvert --type linear vg/lvol1", "content": "Convert a mirror LV to a raid1 LV with the same number of images." }, { "name": "lvconvert --type raid1 vg/lvol1", "content": "Convert a linear LV to a two-way mirror LV, allocating new extents from specific PV ranges." }, { "name": "lvconvert --mirrors 1 vg/lvol1 /dev/sda:0-15 /dev/sdb:0-15", "content": "Convert a mirror LV to a linear LV, freeing physical extents from a specific PV." }, { "name": "lvconvert --type linear vg/lvol1 /dev/sda", "content": "Split one image from a mirror or raid1 LV, making it a new LV." }, { "name": "lvconvert --splitmirrors 1 --name lv_split vg/lvol1", "content": "Split one image from a raid1 LV, and track changes made to the raid1 LV while the split image\nremains detached." }, { "name": "lvconvert --splitmirrors 1 --trackchanges vg/lvol1", "content": "Merge an image (that was previously created with --splitmirrors and --trackchanges) back into\nthe original raid1 LV." }, { "name": "lvconvert --mergemirrors vg/lvol1_rimage_1", "content": "Replace PV /dev/sdb1 with PV /dev/sdf1 in a raid1/4/5/6/10 LV." }, { "name": "lvconvert --replace /dev/sdb1 vg/lvol1 /dev/sdf1", "content": "Replace 3 PVs /dev/sd[b-d]1 with PVs /dev/sd[f-h]1 in a raid1 LV." }, { "name": "lvconvert --replace /dev/sdb1 --replace /dev/sdc1 --replace /dev/sdd1", "content": "vg/lvol1 /dev/sd[fgh]1\n\nReplace the maximum of 2 PVs /dev/sd[bc]1 with PVs /dev/sd[gh]1 in a raid6 LV." }, { "name": "lvconvert --replace /dev/sdb1 --replace /dev/sdc1 vg/lvol1 /dev/sd[gh]1", "content": "Convert an LV into a thin LV in the specified thin pool. The existing LV is used as an ex‐\nternal read-only origin for the new thin LV." }, { "name": "lvconvert --type thin --thinpool vg/tpool1 vg/lvol1", "content": "Convert an LV into a thin LV in the specified thin pool. The existing LV is used as an ex‐\nternal read-only origin for the new thin LV, and is renamed \"external\"." }, { "name": "lvconvert --type thin --thinpool vg/tpool1", "content": "--originname external vg/lvol1\n\nConvert an LV to a cache pool LV using another specified LV for cache pool metadata." }, { "name": "lvconvert --type cache-pool --poolmetadata vg/poolmeta1 vg/lvol1", "content": "Convert an LV to a cache LV using the specified cache pool and chunk size." }, { "name": "lvconvert --type cache --cachepool vg/cpool1 -c 128 vg/lvol1", "content": "Detach and keep the cache pool from a cache LV." }, { "name": "lvconvert --splitcache vg/lvol1", "content": "Detach and remove the cache pool from a cache LV." }, { "name": "lvconvert --uncache vg/lvol1", "content": "" } ] }, "SEE ALSO": { "content": "lvm(8), lvm.conf(5), lvmconfig(8), lvmdevices(8),\n\npvchange(8), pvck(8), pvcreate(8), pvdisplay(8), pvmove(8), pvremove(8), pvresize(8), pvs(8),\npvscan(8),\n\nvgcfgbackup(8), vgcfgrestore(8), vgchange(8), vgck(8), vgcreate(8), vgconvert(8),\nvgdisplay(8), vgexport(8), vgextend(8), vgimport(8), vgimportclone(8), vgimportdevices(8),\nvgmerge(8), vgmknodes(8), vgreduce(8), vgremove(8), vgrename(8), vgs(8), vgscan(8),\nvgsplit(8),\n\nlvcreate(8), lvchange(8), lvconvert(8), lvdisplay(8), lvextend(8), lvreduce(8), lvremove(8),\nlvrename(8), lvresize(8), lvs(8), lvscan(8),\n\nlvm-fullreport(8), lvm-lvpoll(8), blkdeactivate(8), lvmdump(8),\n\ndmeventd(8), lvmpolld(8), lvmlockd(8), lvmlockctl(8), cmirrord(8), lvmdbusd(8), fsadm(8),\n\nlvmsystemid(7), lvmreport(7), lvmraid(7), lvmthin(7), lvmcache(7)\n\nRed Hat, Inc. LVM TOOLS 2.03.16(2) (2022-05-18) LVCONVERT(8)", "subsections": [] } }, "summary": "lvconvert — Change logical volume layout", "flags": [ { "flag": "-b", "long": "--background", "arg": null, "description": "If the operation requires polling, this option causes the command to return before the operation is complete, and polling is done in the background." }, { "flag": "-H", "long": "--cache", "arg": null, "description": "Specifies the command is handling a cache LV or cache pool. See --type cache and --type cache-pool. See lvmcache(7) for more information about LVM caching. --cachedevice PV The name of a device to use for a cache. --cachemetadataformat auto|1|2 Specifies the cache metadata format used by cache target. --cachemode writethrough|writeback|passthrough Specifies when writes to a cache LV should be considered complete. writeback consid‐ ers a write complete as soon as it is stored in the cache pool. writethough considers a write complete only when it has been stored in both the cache pool and on the origin LV. While writethrough may be slower for writes, it is more resilient if something should happen to a device associated with the cache pool LV. With passthrough, all reads are served from the origin LV (all reads miss the cache) and all writes are for‐ warded to the origin LV; additionally, write hits cause cache block invalidates. See lvmcache(7) for more information. --cachepolicy String Specifies the cache policy for a cache LV. See lvmcache(7) for more information. --cachepool LV The name of a cache pool. --cachesettings String Specifies tunable kernel options for dm-cache or dm-writecache LVs. Use the form 'op‐ tion=value' or 'option1=value option2=value', or repeat --cachesettings for each op‐ tion being set. These settings override the default kernel behaviors which are usual‐ ly adequate. To remove cachesettings and revert to the default kernel behaviors, use --cachesettings 'default' for dm-cache or an empty string --cachesettings '' for dm- writecache. See lvmcache(7) for more information. --cachesize Size[m|UNIT] The size of cache to use. --cachevol LV The name of a cache volume." }, { "flag": "-c", "long": "--chunksize", "arg": null, "description": "The size of chunks in a snapshot, cache pool or thin pool. For snapshots, the value must be a power of 2 between 4KiB and 512KiB and the default value is 4. For a cache pool the value must be between 32KiB and 1GiB and the default value is 64. For a thin pool the value must be between 64KiB and 1GiB and the default value starts with 64 and scales up to fit the pool metadata size within 128MiB, if the pool metadata size is not specified. The value must be a multiple of 64KiB. See lvmthin(7) and lvmcache(7) for more information. --commandprofile String The command profile to use for command configuration. See lvm.conf(5) for more infor‐ mation about profiles. --compression y|n Controls whether compression is enabled or disable for VDO volume. See lvmvdo(7) for more information about VDO usage. --config String Config settings for the command. These override lvm.conf(5) settings. The String arg uses the same format as lvm.conf(5), or may use section/field syntax. See lvm.conf(5) for more information about config." }, { "flag": "-d", "long": "--debug", "arg": null, "description": "Set debug level. Repeat from 1 to 6 times to increase the detail of messages sent to the log file and/or syslog (if configured). --deduplication y|n Controls whether deduplication is enabled or disable for VDO volume. See lvmvdo(7) for more information about VDO usage. --devices PV Restricts the devices that are visible and accessible to the command. Devices not listed will appear to be missing. This option can be repeated, or accepts a comma sep‐ arated list of devices. This overrides the devices file. --devicesfile String A file listing devices that LVM should use. The file must exist in /etc/lvm/devices/ and is managed with the lvmdevices(8) command. This overrides the lvm.conf(5) de‐ vices/devicesfile and devices/usedevicesfile settings. --discards passdown|nopassdown|ignore Specifies how the device-mapper thin pool layer in the kernel should handle discards. ignore causes the thin pool to ignore discards. nopassdown causes the thin pool to process discards itself to allow reuse of unneeded extents in the thin pool. passdown causes the thin pool to process discards itself (like nopassdown) and pass the dis‐ cards to the underlying device. See lvmthin(7) for more information. --driverloaded y|n If set to no, the command will not attempt to use device-mapper. For testing and de‐ bugging. --errorwhenfull y|n Specifies thin pool behavior when data space is exhausted. When yes, device-mapper will immediately return an error when a thin pool is full and an I/O request requires space. When no, device-mapper will queue these I/O requests for a period of time to allow the thin pool to be extended. Errors are returned if no space is available af‐ ter the timeout. (Also see dm-thin-pool kernel module option nospacetimeout.) See lvmthin(7) for more information." }, { "flag": "-f", "long": "--force", "arg": null, "description": "Override various checks, confirmations and protections. Use with extreme caution." }, { "flag": "-h", "long": "--help", "arg": null, "description": "Display help text." }, { "flag": "-i", "long": "--interval", "arg": null, "description": "Report progress at regular intervals. --journal String Record information in the systemd journal. This information is in addition to infor‐ mation enabled by the lvm.conf log/journal setting. command: record information about the command. output: record the default command output. debug: record full command debugging. --lockopt String Used to pass options for special cases to lvmlockd. See lvmlockd(8) for more informa‐ tion." }, { "flag": "", "long": "--longhelp", "arg": null, "description": "Display long help text." }, { "flag": "", "long": "--merge", "arg": null, "description": "An alias for --mergethin, --mergemirrors, or --mergesnapshot, depending on the type of LV." }, { "flag": "", "long": "--mergemirrors", "arg": null, "description": "Merge LV images that were split from a raid1 LV. See --splitmirrors with --trackchanges." }, { "flag": "", "long": "--mergesnapshot", "arg": null, "description": "Merge COW snapshot LV into its origin. When merging a snapshot, if both the origin and snapshot LVs are not open, the merge will start immediately. Otherwise, the merge will start the first time either the origin or snapshot LV are activated and both are closed. Merging a snapshot into an origin that cannot be closed, for example a root filesystem, is deferred until the next time the origin volume is activated. When merg‐ ing starts, the resulting LV will have the origin's name, minor number and UUID. While the merge is in progress, reads or writes to the origin appear as being directed to the snapshot being merged. When the merge finishes, the merged snapshot is removed. Multiple snapshots may be specified on the command line or a @tag may be used to spec‐ ify multiple snapshots be merged to their respective origin." }, { "flag": "", "long": "--mergethin", "arg": null, "description": "Merge thin LV into its origin LV. The origin thin LV takes the content of the thin snapshot, and the thin snapshot LV is removed. See lvmthin(7) for more information. --metadataprofile String The metadata profile to use for command configuration. See lvm.conf(5) for more in‐ formation about profiles. --mirrorlog core|disk Specifies the type of mirror log for LVs with the \"mirror\" type (does not apply to the \"raid1\" type.) disk is a persistent log and requires a small amount of storage space, usually on a separate device from the data being mirrored. core is not persistent; the log is kept only in memory. In this case, the mirror must be synchronized (by copying LV data from the first device to others) each time the LV is activated, e.g. after reboot. mirrored is a persistent log that is itself mirrored, but should be avoided. Instead, use the raid1 type for log redundancy." }, { "flag": "-m", "long": "--mirrors", "arg": null, "description": "Specifies the number of mirror images in addition to the original LV image, e.g. --mirrors 1 means there are two images of the data, the original and one mirror image. Optional positional PV args on the command line can specify the devices the images should be placed on. There are two mirroring implementations: \"raid1\" and \"mirror\". These are the names of the corresponding LV types, or \"segment types\". Use the --type option to specify which to use (raid1 is default, and mirror is legacy) Use lvm.conf(5) global/mirrorsegtypedefault and global/raid10segtypedefault to config‐ ure the default types. The plus prefix + can be used, in which case the number is added to the current number of images, or the minus prefix - can be used, in which case the number is subtracted from the current number of images. See lvmraid(7) for more information." }, { "flag": "-n", "long": "--name", "arg": null, "description": "Specifies the name of a new LV. When unspecified, a default name of \"lvol#\" is gener‐ ated, where # is a number generated by LVM." }, { "flag": "", "long": "--nohints", "arg": null, "description": "Do not use the hints file to locate devices for PVs. A command may read more devices to find PVs when hints are not used. The command will still perform standard hint file invalidation where appropriate." }, { "flag": "", "long": "--nolocking", "arg": null, "description": "Disable locking. Use with caution, concurrent commands may produce incorrect results." }, { "flag": "", "long": "--noudevsync", "arg": null, "description": "Disables udev synchronisation. The process will not wait for notification from udev. It will continue irrespective of any possible udev processing in the background. Only use this if udev is not running or has rules that ignore the devices LVM creates. --originname LV Specifies the name to use for the external origin LV when converting an LV to a thin LV. The LV being converted becomes a read-only external origin with this name. --poolmetadata LV The name of a an LV to use for storing pool metadata. --poolmetadatasize Size[m|UNIT] Specifies the size of the new pool metadata LV. --poolmetadataspare y|n Enable or disable the automatic creation and management of a spare pool metadata LV in the VG. A spare metadata LV is reserved space that can be used when repairing a pool. --profile String An alias for --commandprofile or --metadataprofile, depending on the command." }, { "flag": "-q", "long": "--quiet", "arg": null, "description": "Suppress output and log messages. Overrides --debug and --verbose. Repeat once to al‐ so suppress any prompts with answer 'no'. --raidintegrity y|n Enable or disable data integrity checksums for raid images. --raidintegrityblocksize Number The block size to use for dm-integrity on raid images. The integrity block size should usually match the device logical block size, or the file system block size. It may be less than the file system block size, but not less than the device logical block size. Possible values: 512, 1024, 2048, 4096. --raidintegritymode String Use a journal (default) or bitmap for keeping integrity checksums consistent in case of a crash. The bitmap areas are recalculated after a crash, so corruption in those areas would not be detected. A journal does not have this problem. The journal mode doubles writes to storage, but can improve performance for scattered writes packed in‐ to a single journal write. bitmap mode can in theory achieve full write throughput of the device, but would not benefit from the potential scattered write optimization." }, { "flag": "-r", "long": "--readahead", "arg": null, "description": "Sets read ahead sector count of an LV. auto is the default which allows the kernel to choose a suitable value automatically. none is equivalent to zero." }, { "flag": "-R", "long": "--regionsize", "arg": null, "description": "Size of each raid or mirror synchronization region. lvm.conf(5) activation/raidre‐ gionsize can be used to configure a default." }, { "flag": "", "long": "--repair", "arg": null, "description": "Replace failed PVs in a raid or mirror LV, or run a repair utility on a thin pool. See lvmraid(7) and lvmthin(7) for more information. --replace PV Replace a specific PV in a raid LV with another PV. The new PV to use can be option‐ ally specified after the LV. Multiple PVs can be replaced by repeating this option. See lvmraid(7) for more information." }, { "flag": "-s", "long": "--snapshot", "arg": null, "description": "Combine a former COW snapshot LV with a former origin LV to reverse a previous --splitsnapshot command." }, { "flag": "", "long": "--splitcache", "arg": null, "description": "Separates a cache pool from a cache LV, and keeps the unused cache pool LV. Before the separation, the cache is flushed. Also see --uncache. --splitmirrors Number Splits the specified number of images from a raid1 or mirror LV and uses them to cre‐ ate a new LV. If --trackchanges is also specified, changes to the raid1 LV are tracked while the split LV remains detached. If --name is specified, then the images are per‐ manently split from the original LV and changes are not tracked." }, { "flag": "", "long": "--splitsnapshot", "arg": null, "description": "Separates a COW snapshot from its origin LV. The LV that is split off contains the chunks that differ from the origin LV along with metadata describing them. This LV can be wiped and then destroyed with lvremove." }, { "flag": "", "long": "--startpoll", "arg": null, "description": "Start polling an LV to continue processing a conversion. --stripes Number Specifies the number of stripes in a striped LV. This is the number of PVs (devices) that a striped LV is spread across. Data that appears sequential in the LV is spread across multiple devices in units of the stripe size (see --stripesize). This does not apply to existing allocated space, only newly allocated space can be striped." }, { "flag": "-I", "long": "--stripesize", "arg": null, "description": "The amount of data that is written to one device before moving to the next in a striped LV." }, { "flag": "", "long": "--swapmetadata", "arg": null, "description": "Extracts the metadata LV from a pool and replaces it with another specified LV. The extracted LV is preserved and given the name of the LV that replaced it. Use for re‐ pair only. When the metadata LV is swapped out of the pool, it can be activated di‐ rectly and used with thin provisioning tools: cachedump(8), cacherepair(8), cacherestore(8), thindump(8), thinrepair(8), thinrestore(8)." }, { "flag": "-t", "long": "--test", "arg": null, "description": "Run in test mode. Commands will not update metadata. This is implemented by disabling all metadata writing but nevertheless returning success to the calling function. This may lead to unusual error messages in multi-stage operations if a tool relies on read‐ ing back metadata it believes has changed but hasn't." }, { "flag": "-T", "long": "--thin", "arg": null, "description": "Specifies the command is handling a thin LV or thin pool. See --type thin, --type thin-pool, and --virtualsize. See lvmthin(7) for more information about LVM thin pro‐ visioning. --thinpool LV The name of a thin pool LV." }, { "flag": "", "long": "--trackchanges", "arg": null, "description": "Can be used with --splitmirrors on a raid1 LV. This causes changes to the original raid1 LV to be tracked while the split images remain detached. This is a temporary state that allows the read-only detached image to be merged efficiently back into the raid1 LV later. Only the regions with changed data are resynchronized during merge. While a raid1 LV is tracking changes, operations on it are limited to merging the split image (see --mergemirrors) or permanently splitting the image (see --splitmir‐ rors with --name. --type linear|striped|snapshot|raid|mirror|thin|thin-pool|vdo|vdo-pool|cache|cache-pool| writecache The LV type, also known as \"segment type\" or \"segtype\". See usage descriptions for the specific ways to use these types. For more information about redundancy and per‐ formance (raid, mirror, striped, linear) see lvmraid(7). For thin provisioning (thin, thin-pool) see lvmthin(7). For performance caching (cache, cache-pool) see lvmcache(7). For copy-on-write snapshots (snapshot) see usage definitions. For VDO (vdo) see lvmvdo(7). Several commands omit an explicit type option because the type is inferred from other options or shortcuts (e.g. --stripes, --mirrors, --snapshot, --virtualsize, --thin, --cache, --vdo). Use inferred types with care because it can lead to unexpected results." }, { "flag": "", "long": "--uncache", "arg": null, "description": "Separates a cache pool from a cache LV, and deletes the unused cache pool LV. Before the separation, the cache is flushed. Also see --splitcache." }, { "flag": "", "long": "--usepolicies", "arg": null, "description": "Perform an operation according to the policy configured in lvm.conf(5) or a profile. --vdopool LV The name of a VDO pool LV. See lvmvdo(7) for more information about VDO usage. --vdosettings String Specifies tunable VDO options for VDO LVs. Use the form 'option=value' or 'op‐ tion1=value option2=value', or repeat --vdosettings for each option being set. These settings override the default VDO behaviors. To remove vdosettings and revert to the default VDO behaviors, use --vdosettings 'default'. See lvmvdo(7) for more informa‐ tion." }, { "flag": "-v", "long": "--verbose", "arg": null, "description": "Set verbose level. Repeat from 1 to 4 times to increase the detail of messages sent to stdout and stderr." }, { "flag": "", "long": "--version", "arg": null, "description": "Display version information." }, { "flag": "-V", "long": "--virtualsize", "arg": null, "description": "The virtual size of a new thin LV. See lvmthin(7) for more information about LVM thin provisioning. Using virtual size (-V) and actual size (-L) together creates a sparse LV. lvm.conf(5) global/sparsesegtypedefault determines the default segment type used to create a sparse LV. Anything written to a sparse LV will be returned when reading from it. Reading from other areas of the LV will return blocks of zeros. When using a snapshot to create a sparse LV, a hidden virtual device is created using the zero target, and the LV has the suffix vorigin. Snapshots are less efficient than thin provisioning when creating large sparse LVs (GiB)." }, { "flag": "-y", "long": "--yes", "arg": null, "description": "Do not prompt for confirmation interactively but always assume the answer yes. Use with extreme caution. (For automatic no, see -qq.)" }, { "flag": "-Z", "long": "--zero", "arg": null, "description": "For snapshots, this controls zeroing of the first 4KiB of data in the snapshot. If the LV is read-only, the snapshot will not be zeroed. For thin pools, this controls zero‐ ing of provisioned blocks. Provisioning of large zeroed chunks negatively impacts performance." } ], "examples": [ "Convert a linear LV to a two-way mirror LV.", "Convert a linear LV to a two-way RAID1 LV.", "Convert a mirror LV to use an in-memory log.", "Convert a mirror LV to use a disk log.", "Convert a mirror or raid1 LV to a linear LV.", "Convert a mirror LV to a raid1 LV with the same number of images.", "Convert a linear LV to a two-way mirror LV, allocating new extents from specific PV ranges.", "Convert a mirror LV to a linear LV, freeing physical extents from a specific PV.", "Split one image from a mirror or raid1 LV, making it a new LV.", "Split one image from a raid1 LV, and track changes made to the raid1 LV while the split image", "remains detached.", "Merge an image (that was previously created with --splitmirrors and --trackchanges) back into", "the original raid1 LV.", "Replace PV /dev/sdb1 with PV /dev/sdf1 in a raid1/4/5/6/10 LV.", "Replace 3 PVs /dev/sd[b-d]1 with PVs /dev/sd[f-h]1 in a raid1 LV.", "vg/lvol1 /dev/sd[fgh]1", "Replace the maximum of 2 PVs /dev/sd[bc]1 with PVs /dev/sd[gh]1 in a raid6 LV.", "Convert an LV into a thin LV in the specified thin pool. The existing LV is used as an ex‐", "ternal read-only origin for the new thin LV.", "Convert an LV into a thin LV in the specified thin pool. The existing LV is used as an ex‐", "ternal read-only origin for the new thin LV, and is renamed \"external\".", "--originname external vg/lvol1", "Convert an LV to a cache pool LV using another specified LV for cache pool metadata.", "Convert an LV to a cache LV using the specified cache pool and chunk size.", "Detach and keep the cache pool from a cache LV.", "Detach and remove the cache pool from a cache LV." ], "see_also": [ { "name": "lvm", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvm/8/json" }, { "name": "lvm.conf", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/lvm.conf/5/json" }, { "name": "lvmconfig", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvmconfig/8/json" }, { "name": "lvmdevices", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvmdevices/8/json" }, { "name": "pvchange", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/pvchange/8/json" }, { "name": "pvck", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/pvck/8/json" }, { "name": "pvcreate", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/pvcreate/8/json" }, { "name": "pvdisplay", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/pvdisplay/8/json" }, { "name": "pvmove", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/pvmove/8/json" }, { "name": "pvremove", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/pvremove/8/json" }, { "name": "pvresize", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/pvresize/8/json" }, { "name": "pvs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/pvs/8/json" }, { "name": "pvscan", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/pvscan/8/json" }, { "name": "vgcfgbackup", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgcfgbackup/8/json" }, { "name": "vgcfgrestore", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgcfgrestore/8/json" }, { "name": "vgchange", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgchange/8/json" }, { "name": "vgck", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgck/8/json" }, { "name": "vgcreate", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgcreate/8/json" }, { "name": "vgconvert", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgconvert/8/json" }, { "name": "vgdisplay", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgdisplay/8/json" }, { "name": "vgexport", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgexport/8/json" }, { "name": "vgextend", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgextend/8/json" }, { "name": "vgimport", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgimport/8/json" }, { "name": "vgimportclone", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgimportclone/8/json" }, { "name": "vgimportdevices", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgimportdevices/8/json" }, { "name": "vgmerge", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgmerge/8/json" }, { "name": "vgmknodes", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgmknodes/8/json" }, { "name": "vgreduce", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgreduce/8/json" }, { "name": "vgremove", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgremove/8/json" }, { "name": "vgrename", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgrename/8/json" }, { "name": "vgs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgs/8/json" }, { "name": "vgscan", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgscan/8/json" }, { "name": "vgsplit", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/vgsplit/8/json" }, { "name": "lvcreate", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvcreate/8/json" }, { "name": "lvchange", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvchange/8/json" }, { "name": "lvdisplay", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvdisplay/8/json" }, { "name": "lvextend", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvextend/8/json" }, { "name": "lvreduce", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvreduce/8/json" }, { "name": "lvremove", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvremove/8/json" }, { "name": "lvrename", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvrename/8/json" }, { "name": "lvresize", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvresize/8/json" }, { "name": "lvs", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvs/8/json" }, { "name": "lvscan", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvscan/8/json" }, { "name": "lvm-fullreport", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvm-fullreport/8/json" }, { "name": "lvm-lvpoll", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvm-lvpoll/8/json" }, { "name": "blkdeactivate", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/blkdeactivate/8/json" }, { "name": "lvmdump", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvmdump/8/json" }, { "name": "dmeventd", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/dmeventd/8/json" }, { "name": "lvmpolld", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvmpolld/8/json" }, { "name": "lvmlockd", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvmlockd/8/json" }, { "name": "lvmlockctl", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvmlockctl/8/json" }, { "name": "cmirrord", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/cmirrord/8/json" }, { "name": "lvmdbusd", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/lvmdbusd/8/json" }, { "name": "fsadm", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/fsadm/8/json" }, { "name": "lvmsystemid", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/lvmsystemid/7/json" }, { "name": "lvmreport", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/lvmreport/7/json" }, { "name": "lvmraid", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/lvmraid/7/json" }, { "name": "lvmthin", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/lvmthin/7/json" }, { "name": "lvmcache", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/lvmcache/7/json" } ] }