{
    "mode": "man",
    "parameter": "xfsdump",
    "section": "8",
    "url": "https://www.chedong.com/phpMan.php/man/xfsdump/8/json",
    "generated": "2026-07-05T02:11:12Z",
    "synopsis": "xfsdump -h\nxfsdump [ options ] -f dest [ -f dest ... ] filesystem\nxfsdump [ options ] - filesystem\nxfsdump -I [ subopt=value ... ]",
    "sections": {
        "NAME": {
            "content": "xfsdump - XFS filesystem incremental dump utility\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "xfsdump -h\nxfsdump [ options ] -f dest [ -f dest ... ] filesystem\nxfsdump [ options ] - filesystem\nxfsdump -I [ subopt=value ... ]\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "xfsdump backs up files and their attributes in a filesystem.  The files are dumped to storage\nmedia, a regular file, or standard output.  Options allow the  operator  to  have  all  files\ndumped, just files that have changed since a previous dump, or just files contained in a list\nof pathnames.\n\nThe xfsrestore(8) utility re-populates a filesystem with the contents of the dump.\n\nEach invocation of xfsdump dumps just one filesystem.  That invocation is termed a dump  ses‐\nsion.  The dump session splits the filesystem into one or more dump streams, one per destina‐\ntion.  The split is done in filesystem inode number (ino) order, at  boundaries  selected  to\nequalize the size of each stream.  Furthermore, the breakpoints between streams may be in the\nmiddle of very large files (at extent boundaries) if necessary to achieve  reasonable  stream\nsize  equalization.   Each dump stream can span several media objects, and a single media ob‐\nject can contain several dump streams.  The typical media object is a  tape  cartridge.   The\nmedia object records the dump stream as one or more media files.  A media file is a self-con‐\ntained partial dump, intended to minimize the impact of media dropouts  on  the  entire  dump\nstream  at  the expense of increasing the time required to complete the dump. By default only\none media file is written unless a media file size is specified using the  -d  option.  Other\ntechniques,  such  as making a second copy of the dump image, provide more protection against\nmedia failures than multiple media files will.\n\nxfsdump maintains an online dump inventory in /var/lib/xfsdump/inventory.  The -I option dis‐\nplays  the  inventory  contents hierarchically.  The levels of the hierarchy are: filesystem,\ndump session, stream, and media file.\n\nThe options to xfsdump are:\n",
            "subsections": [
                {
                    "name": "-a",
                    "content": "copies (dual-state files) be treated as if they were offline (OFL).  This means that the\nfile data will not be dumped by xfsdump, resulting in a smaller dump file.  If the  file\nis  later  restored  the file data is still accessible through DMF.  If both '-a option'\nand '-z option' are specified, the '-a option' takes precedence (see '-z option' below).\n",
                    "flag": "-a"
                },
                {
                    "name": "-b",
                    "content": "Specifies the blocksize, in bytes, to be used for the dump.  The same blocksize must  be\nspecified  to  restore the tape.  If the -m option is not used, then -b does not need to\nbe specified. Instead, a default blocksize of 1Mb will be used.\n",
                    "flag": "-b"
                },
                {
                    "name": "-c",
                    "content": "Use the specified program to alert the operator when a media  change  is  required.  The\nalert  program is typically a script to send a mail or flash a window to draw the opera‐\ntor's attention.\n",
                    "flag": "-c"
                },
                {
                    "name": "-d",
                    "content": "Specifies the size, in megabytes, of dump media files.  If not specified,  xfsdump  will\ndump  data to tape using a single media file per media object.  The specified media file\nsize may need to be adjusted if, for example, xfsdump cannot fit a  media  file  onto  a\nsingle tape.\n",
                    "flag": "-d"
                },
                {
                    "name": "-e",
                    "content": "have the \"no dump\" file attribute set. See the \"Excluding individual files\" section  be‐\nlow for details on setting this file attribute.\n",
                    "flag": "-e"
                },
                {
                    "name": "-f -f",
                    "content": "Specifies  a dump destination.  A dump destination can be the pathname of a device (such\nas a tape drive), a regular file or a remote tape drive (see rmt(8)).  This option  must\nbe omitted if the standard output option (a lone - preceding the source filesystem spec‐\nification) is specified.\n",
                    "flag": "-f"
                },
                {
                    "name": "-l",
                    "content": "Specifies a dump level of 0 to 9.  The dump level determines the base dump to which this\ndump  is  relative.  The base dump is the most recent dump at a lesser level.  A level 0\ndump is absolute - all files are dumped.  A dump level where 1 <= level <= 9 is referred\nto  as  an  incremental dump.  Only files that have been changed since the base dump are\ndumped.  Subtree dumps (see the -s option below) cannot be used as the base  for  incre‐\nmental dumps.\n",
                    "flag": "-l"
                },
                {
                    "name": "-m",
                    "content": "which are not scsi Linux tape drives nor IRIX tape drives.  This option cannot  be  used\nwithout specifying a blocksize to be used (see -b option above).\n",
                    "flag": "-m"
                },
                {
                    "name": "-o",
                    "content": "contents. This option may be used if xfsdump is unable to determine the block size of  a\ntape .\n",
                    "flag": "-o"
                },
                {
                    "name": "-p",
                    "content": "Causes  progress  reports to be printed at the specified interval.  interval is given in\nseconds.  The progress report indicates how many files have been dumped, the total  num‐\nber of files to dump, the percentage of data dumped, and the elapsed time.\n",
                    "flag": "-p"
                },
                {
                    "name": "-q",
                    "content": "which xfsdump must make special allowances.\n",
                    "flag": "-q"
                },
                {
                    "name": "-s -s",
                    "content": "Restricts the dump to files contained in the specified pathnames (subtrees).  A pathname\nmust  be relative to the mount point of the filesystem.  For example, if a filesystem is\nmounted at /d2, the pathname argument for the directory /d2/users is ``users''.  A path‐\nname  can  be a file or a directory; if it is a directory, the entire hierarchy of files\nand subdirectories rooted at that directory is dumped.  Subtree dumps cannot be used  as\nthe base for incremental dumps (see the -l option above).\n",
                    "flag": "-s"
                },
                {
                    "name": "-t",
                    "content": "Sets  the dump time to the modification time of file rather than using the current time.\nxfsdump uses the dump time to determine what files need to be backed up during an incre‐\nmental  dump.  This  option  should be used when dumping snapshots so that the dump time\nmatches the time the snapshot was taken. Otherwise files modified after  a  snapshot  is\ntaken may be skipped in the next incremental dump.\n",
                    "flag": "-t"
                },
                {
                    "name": "-v",
                    "content": "",
                    "flag": "-v"
                },
                {
                    "name": "-v",
                    "content": "Specifies the level of detail used for messages displayed during the course of the dump.\nThe verbosity argument can be passed as either a string or an integer. If  passed  as  a\nstring  the  following  values may be used: silent, verbose, trace, debug, or nitty.  If\npassed as an integer, values from 0-5 may be used. The  values  0-4  correspond  to  the\nstrings  already listed. The value 5 can be used to produce even more verbose debug out‐\nput.\n\nThe first form of this option activates message logging across all dump subsystems.  The\nsecond  form allows the message logging level to be controlled on a per-subsystem basis.\nThe two forms can be combined (see the example below). The argument subsys can take  one\nof  the  following  values:  general,  proc,  drive,  media,  inventory,  inomap and ex‐‐\ncludedfiles.\n\nFor example, to dump the root filesystem with tracing activated for all subsystems:\n\n# xfsdump -v trace -f /dev/tape /\n\nTo enable debug-level tracing for drive and media operations:\n\n# xfsdump -v drive=debug,media=debug -f /dev/tape /\n\nTo enable tracing for all subsystems, and debug level tracing for drive operations only:\n\n# xfsdump -v trace,drive=debug -f /dev/tape /\n\nTo list files that will be excluded from the dump:\n\n# xfsdump -e -v excludedfiles=debug -f /dev/tape /\n\n",
                    "flag": "-v"
                },
                {
                    "name": "-z",
                    "content": "Specifies the maximum size, in kilobytes, of files to be included in  the  dump.   Files\nover this size, will be excluded from the dump, except for DMF dual-state files when '-a\noption' is specified (see '-a option' above).  When specified, '-a option' takes  prece‐\ndence over '-z option'. The size is an estimate based on the number of disk blocks actu‐\nally used by the file, and so does not include holes.  In other words,  size  refers  to\nthe  amount  of  space the file would take in the resulting dump.  On an interactive re‐\nstore, the skipped file is visible with xfsrestore's 'ls' and  while  you  can  use  the\n'add' and 'extract' commands, nothing will be restored.\n",
                    "flag": "-z"
                },
                {
                    "name": "-A",
                    "content": "environment this option should not be used. DMF stores file migration status within  ex‐\ntended  attributes associated with each file. If these attributes are not preserved when\nthe filesystem is restored, files that had been in migrated state will not be recallable\nby  DMF.  Note  that  dumps  containing extended file attributes cannot be restored with\nolder versions of xfsrestore(8).\n",
                    "flag": "-A"
                },
                {
                    "name": "-B",
                    "content": "Specifies the ID of the dump session upon which this dump session is to  be  based.   If\nthis  option  is specified, the -l (level) and -R (resume) options are not allowed.  In‐\nstead, xfsdump determines if the current dump session should be incremental  and/or  re‐\nsumed,  by  looking at the base session's level and interrupted attributes.  If the base\nsession was interrupted, the current dump session is a resumption of that  base  at  the\nsame level.  Otherwise, the current dump session is an incremental dump with a level one\ngreater than that of the base session.  This option allows incremental and resumed dumps\nto be based on any previous dump, rather than just the most recent.\n",
                    "flag": "-B"
                },
                {
                    "name": "-D",
                    "content": "changed directories are dumped if files or directories beneath them have  changed.  This\nresults  in a self-contained dump -- if a base dump is lost, or you know the file(s) you\nwish to restore is in an incremental dump, you can restore just that dump without  load‐\ning  the  base dump(s) first. However, this method requires a potentially expensive tra‐\nversal through the filesystem.\n\nWhen -D is specified, unchanged directories are not dumped.  This results  in  a  faster\ndump,  but  files  will  end up in the xfsrestore(8) orphanage directory unless the base\ndump(s) is loaded first.\n",
                    "flag": "-D"
                },
                {
                    "name": "-E",
                    "content": "tor is prompted for confirmation, unless the -F option is also specified.\n",
                    "flag": "-E"
                },
                {
                    "name": "-F",
                    "content": "dump data, xfsdump normally asks the operator for permission to  overwrite.   With  this\noption  the overwrite is performed, no questions asked.  When xfsdump encounters end-of-\nmedia during a dump, xfsdump normally asks the operator if another media object will  be\nprovided.  With this option the dump is instead interrupted.\n",
                    "flag": "-F"
                },
                {
                    "name": "-I",
                    "content": "sion in an online inventory in /var/lib/xfsdump/inventory.  xfsdump uses this  inventory\nto determine the base for incremental dumps.  It is also useful for manually identifying\na dump session to be restored.  Suboptions to filter the inventory display are described\nlater.\n",
                    "flag": "-I"
                },
                {
                    "name": "-J",
                    "content": "to will be discarded or overwritten.\n",
                    "flag": "-J"
                },
                {
                    "name": "-K",
                    "content": "be  restored  on a system with an older xfsrestore which does not understand the current\ndump format. Use of this option is otherwise not recommended.\n",
                    "flag": "-K"
                },
                {
                    "name": "-L",
                    "content": "Specifies a label for the dump session.  It can be any arbitrary string up to 255  char‐\nacters long.\n",
                    "flag": "-L"
                },
                {
                    "name": "-M -M",
                    "content": "Specifies  a  label  for the first media object (for example, tape cartridge) written on\nthe corresponding destination during the session.  It can be any arbitrary string up  to\n255 characters long.  Multiple media object labels can be specified, one for each desti‐\nnation.\n",
                    "flag": "-M"
                },
                {
                    "name": "-O",
                    "content": "Insert the options contained in optionsfile into the beginning  of  the  command  line.\nThe  options are specified just as they would appear if typed into the command line.  In\naddition, newline characters (\\n) can be used as whitespace.  The options are placed be‐\nfore  all options actually given on the command line, just after the command name.  Only\none -O option can be used.  Recursive use is ignored.  The source filesystem  cannot  be\nspecified in optionsfile.\n",
                    "flag": "-O"
                },
                {
                    "name": "-R",
                    "content": "level (-l option) was interrupted, this dump contains only files not in the  interrupted\ndump  and consistent with the incremental level.  However, files contained in the inter‐\nrupted dump that have been subsequently modified are re-dumped.\n",
                    "flag": "-R"
                },
                {
                    "name": "-T -F",
                    "content": "prompts  the operator for labels and media changes.  Each dialogue normally times out if\nno response is supplied.  This option prevents the timeout.\n",
                    "flag": "-F"
                },
                {
                    "name": "-Y",
                    "content": "Specify I/O buffer ring length.  xfsdump uses a ring of output buffers to achieve  maxi‐\nmum  throughput  when  dumping  to tape drives.  The default ring length is 3.  However,\nthis is not currently enabled on Linux yet, making this option benign.\n\n-    A lone - causes the dump stream to be sent to the standard output, where it can be piped\nto another utility such as xfsrestore(8) or redirected to a file.  This option cannot be\nused with the -f option.  The - must follow all other options and precede the filesystem\nspecification.\n\nThe  filesystem,  filesystem, can be specified either as a mount point or as a special device\nfile (for example, /dev/dsk/dks0d1s0).  The filesystem must be mounted to be dumped.\n",
                    "flag": "-Y"
                }
            ]
        },
        "NOTES": {
            "content": "",
            "subsections": [
                {
                    "name": "Dump Interruption",
                    "content": "A dump can be interrupted at any time and later resumed.  To interrupt,  type  control-C  (or\nthe current terminal interrupt character).  The operator is prompted to select one of several\noperations, including dump interruption.  After the operator selects dump  interruption,  the\ndump  continues  until a convenient break point is encountered (typically the end of the cur‐\nrent file).  Very large files are broken into smaller subfiles, so the wait for  the  end  of\nthe current file is brief.\n"
                },
                {
                    "name": "Dump Resumption",
                    "content": "A previously interrupted dump can be resumed by specifying the -R option.  If the most recent\ndump at the specified level was interrupted, the new dump  does  not  include  files  already\ndumped, unless they have changed since the interrupted dump.\n"
                },
                {
                    "name": "Media Management",
                    "content": "A  single  media  object can contain many dump streams.  Conversely, a single dump stream can\nspan multiple media objects.  If a dump stream is sent to a media object  already  containing\none  or  more  dumps,  xfsdump appends the new dump stream after the last dump stream.  Media\nfiles are never overwritten.  If end-of-media is encountered during the course of a dump, the\noperator  is prompted to insert a new media object into the drive.  The dump stream continua‐\ntion is appended after the last media file on the new media object.\n"
                },
                {
                    "name": "Inventory",
                    "content": "Each dump session updates an inventory database in /var/lib/xfsdump/inventory.  xfsdump  uses\nthe inventory to determine the base of incremental and resumed dumps.\n\nThis  database  can  be  displayed  by invoking xfsdump with the -I option.  The display uses\ntabbed indentation to present the inventory hierarchically.  The first level  is  filesystem.\nThe  second  level is session.  The third level is media stream (currently only one stream is\nsupported).  The fourth level lists the media files sequentially composing the stream.\n\nThe following suboptions are available to filter the display.\n"
                },
                {
                    "name": "-I",
                    "content": "(where n is 1, 2, or 3) limits the hierarchical depth of the display. When n is 1,  only\nthe filesystem information from the inventory is displayed. When n is 2, only filesystem\nand session information are displayed. When n is 3, only filesystem, session and  stream\ninformation are displayed.\n",
                    "flag": "-I"
                },
                {
                    "name": "-I",
                    "content": "(where n is the dump level) limits the display to dumps of that particular dump level.\n\nThe display may be restricted to media files contained in a specific media object.\n",
                    "flag": "-I"
                },
                {
                    "name": "-I",
                    "content": "(where value is a media ID) specifies the media object by its media ID.\n",
                    "flag": "-I"
                },
                {
                    "name": "-I",
                    "content": "(where value is a media label) specifies the media object by its media label.\n\nSimilarly, the display can be restricted to a specific filesystem.\n",
                    "flag": "-I"
                },
                {
                    "name": "-I",
                    "content": "(that is, [hostname:]pathname), identifies the filesystem by mountpoint.  Specifying the\nhostname is optional, but may be useful in a clustered environment where more  than  one\nhost can be responsible for dumping a filesystem.\n",
                    "flag": "-I"
                },
                {
                    "name": "-I",
                    "content": "identifies the filesystem by filesystem ID.\n",
                    "flag": "-I"
                },
                {
                    "name": "-I",
                    "content": "(that  is,  [hostname:]devicepathname) identifies the filesystem by device. As with the\nmnt filter, specifying the hostname is optional.\n\nMore than one of these suboptions, separated by commas, may be specified at the same time  to\nlimit  the display of the inventory to those dumps of interest.  However, at most four subop‐\ntions can be specified at once: one to constrain the display hierarchy  depth,  one  to  con‐\nstrain  the  dump level, one to constrain the media object, and one to constrain the filesys‐\ntem.\n\nFor  example,  -I  depth=1,mobjlabel=\"tape  1\",mnt=host1:/testmnt  would  display  only  the\nfilesystem  information  (depth=1) for those filesystems that were mounted on host1:/testmnt\nat the time of the dump, and only those filesystems dumped to the media object labeled  \"tape\n1\".\n\nDump records may be removed (pruned) from the inventory using the xfsinvutil program.\n\nAn  additional media file is placed at the end of each dump stream.  This media file contains\nthe inventory information for the current dump session.  Its contents may be merged back into\nthe online inventory database at a later time using xfsrestore(1M).\n\nThe inventory files stored in /var/lib/xfsdump are not included in the dump, even if that di‐\nrectory is contained within the filesystem being dumped.  Including the inventory in the dump\nmay  lead  to loss or corruption of data, should an older version be restored overwriting the\ncurrent version.  To backup the xfsdump inventory, the contents of /var/lib/xfsdump should be\ncopied  to  another  location which may then be safely dumped.  Upon restoration, those files\nmay be copied back into /var/lib/xfsdump, overwriting whatever files may be there, or  xfsin‐\nvutil(1M) may be used to selectively merge parts of the restored inventory back into the cur‐\nrent inventory.  Prior to version 1.1.8, xfsdump would include the /var/lib/xfsdump directory\nin  the  dump.   Care  should  be  taken not to overwrite the /var/lib/xfsdump directory when\nrestoring an old dump, by either restoring the filesystem to another location or  by  copying\nthe current contents of /var/lib/xfsdump to a safe place prior to running xfsrestore(1M).\n",
                    "flag": "-I"
                },
                {
                    "name": "Labels",
                    "content": "The operator can specify a label to identify the dump session and a label to identify a media\nobject.  The session label is placed in every media file produced in the course of the  dump,\nand is recorded in the inventory.\n\nThe  media  label is used to identify media objects, and is independent of the session label.\nEach media file on the media object contains a copy of the media label.  An error is returned\nif the operator specifies a media label that does not match the media label on a media object\ncontaining valid media files.  Media labels are recorded in the inventory.\n"
                },
                {
                    "name": "UUIDs",
                    "content": "UUIDs (Universally Unique Identifiers) are used in three places: to identify  the  filesystem\nbeing  dumped  (using the filesystem UUID, see xfs(5) for more details), to identify the dump\nsession, and to identify each media object.  The  inventory  display  (-I)  includes  all  of\nthese.\n"
                },
                {
                    "name": "Dump Level Usage",
                    "content": "The  dump  level  mechanism provides a structured form of incremental dumps.  A dump of level\nlevel includes only files that have changed since the most recent dump at a level  less  than\nlevel.  For example, the operator can establish a dump schedule that involves a full dump ev‐\nery Friday and a daily incremental dump containing only files that  have  changed  since  the\nprevious  dump.   In this case Friday's dump would be at level 0, Saturday's at level 1, Sun‐\nday's at level 2, and so on, up to the Thursday dump at level 6.\n\nThe above schedule results in a very tedious  restore  procedure  to  fully  reconstruct  the\nThursday  version of the filesystem; xfsrestore would need to be fed all 7 dumps in sequence.\nA compromise schedule is to use level 1 on Saturday, Monday, and Wednesday, and  level  2  on\nSunday,  Tuesday,  and  Thursday.   The Monday and Wednesday dumps would take longer, but the\nworst case restore requires the accumulation of just three dumps, one each at level 0,  level\n1, and level 2.\n"
                },
                {
                    "name": "Quotas",
                    "content": "If  the  filesystem being dumped contains user quotas, xfsdump will use xfsquota(8) to store\nthe quotas in a file called xfsdumpquotas in the root of the filesystem to be  dumped.  This\nfile will then be included in the dump.  Upon restoration, xfsquota (8) can be used to reac‐\ntivate the quotas for the filesystem.  Note, however, that the xfsdumpquotas file will prob‐\nably  require  modification  to  change the filesystem or UIDs if the filesystem has been re‐\nstored to a different partition or system. Group and project quotas will be handled in a sim‐\nilar fashion and saved in files called xfsdumpquotasgroup and xfsdumpquotasproj , respec‐\ntively.\n"
                },
                {
                    "name": "Excluding individual files",
                    "content": "It may be desirable to exclude particular files or directories from the dump.  The -s  option\ncan  be used to limit the dump to a specified directory, and the -z option can be used to ex‐\nclude files over a particular size.  Additionally, when xfsdump is run with  the  -e  option,\nfiles  that  are  tagged  with the \"no dump\" file attribute will not be included in the dump.\nThe chattr(1) command can be used to set this attribute on individual files  or  entire  sub‐\ntrees.\n\nTo tag an individual file for exclusion from the dump:\n\n$ chattr +d file\n\nTo tag all files in a subtree for exclusion from the dump:\n\n$ chattr -R +d directory\n\nNote  that any new files or directories created in a directory which has the \"no dump\" attri‐\nbute set will automatically inherit this attribute.  Also note that xfsdump  does  not  check\ndirectories for the \"no dump\" attribute.\n\nCare  should  be taken to note which files have been tagged.  Under normal operation, xfsdump\nwill only report the number of files it will skip.  The -v excludedfiles=debug option,  how‐\never, will cause xfsdump to list the inode numbers of the individual files affected.\n"
                }
            ]
        },
        "EXAMPLES": {
            "content": "To  perform  a  level  0, single stream dump of the root filesystem to a locally mounted tape\ndrive, prompting for session and media labels when required:\n\n# xfsdump -f /dev/tape /\n\nTo specify session and media labels explicitly:\n\n# xfsdump -L session1 -M tape0 -f /dev/tape /\n\nTo perform a dump to a remote tape using the minimal rmt protocol and a set blocksize of 64k:\n\n# xfsdump -m -b 65536 -f otherhost:/dev/tape /\n\nTo perform a level 0, multi-stream dump to two locally mounted tape drives:\n\n# xfsdump -L session2 -f /dev/rmt/tps4d6v -M tape1 \\\n-f /dev/rmt/tps5d6v -M tape2 /\n\nTo perform a level 1 dump relative to the last level 0 dump recorded in the inventory:\n\n# xfsdump -l 1 -f /dev/tape /\n\nTo copy the contents of a filesystem to another directory (see xfsrestore(8)):\n\n# xfsdump -J - / | xfsrestore -J - /new\n\n",
            "subsections": []
        },
        "FILES": {
            "content": "/var/lib/xfsdump/inventory\ndump inventory database\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "attr(1), rmt(8), xfsrestore(8), xfsinvutil(8), xfsquota(8), attrget(2).\n",
            "subsections": []
        },
        "DIAGNOSTICS": {
            "content": "The exit code is 0 on normal completion, non-zero if an error occurs or the  dump  is  termi‐\nnated by the operator.\n\nFor  all verbosity levels greater than 0 (silent) the final line of the output shows the exit\nstatus of the dump. It is of the form:\n\nxfsdump: Dump Status: code\n\nWhere code takes one of the following values: SUCCESS (normal completion), INTERRUPT  (inter‐\nrupted), QUIT (media no longer usable), INCOMPLETE (dump incomplete), FAULT (software error),\nand ERROR (resource error).  Every attempt will be made to keep both the syntax and  the  se‐\nmantics of this log message unchanged in future versions of xfsdump.  However, it may be nec‐\nessary to refine or expand the set of exit codes, or their interpretation at  some  point  in\nthe future.\n\nThe message ``xfsdump: WARNING: unable to open directory: ino N: Invalid argument'' can occur\nwith filesystems which are actively being modified while xfsdump is running.  This can happen\nto  either  directory  or  regular  file inodes - affected files will not end up in the dump,\nfiles below affected directories will be placed in the orphanage directory by xfsrestore.\n",
            "subsections": []
        },
        "BUGS": {
            "content": "xfsdump does not dump unmounted filesystems.\n\nThe dump frequency field of /etc/fstab is not supported.\n\nxfsdump uses the alert program only when a media change is required.\n\nxfsdump requires root privilege (except for inventory display).\n\nxfsdump can only dump XFS filesystems.\n\nThe media format used by xfsdump can only be understood by xfsrestore.\n\nxfsdump does not know how to manage CD-ROM or other removable disk drives.\n\nxfsdump can become confused when doing incremental or resumed dumps if on  the  same  machine\nyou dump two XFS filesystems and both filesystems have the same filesystem identifier (UUID).\nSince xfsdump uses the filesystem identifier to identify filesystems, xfsdump  maintains  one\ncombined  set  of  dump inventories for both filesystems instead of two sets of dump invento‐\nries.  This scenario can happen only if dd or some other block-by-block copy program was used\nto make a copy of an XFS filesystem.  See xfscopy(8) and xfs(5) for more details.\n\n\n\nxfsdump(8)",
            "subsections": []
        }
    },
    "summary": "xfsdump - XFS filesystem incremental dump utility",
    "flags": [
        {
            "flag": "-a",
            "long": null,
            "arg": null,
            "description": "copies (dual-state files) be treated as if they were offline (OFL). This means that the file data will not be dumped by xfsdump, resulting in a smaller dump file. If the file is later restored the file data is still accessible through DMF. If both '-a option' and '-z option' are specified, the '-a option' takes precedence (see '-z option' below)."
        },
        {
            "flag": "-b",
            "long": null,
            "arg": null,
            "description": "Specifies the blocksize, in bytes, to be used for the dump. The same blocksize must be specified to restore the tape. If the -m option is not used, then -b does not need to be specified. Instead, a default blocksize of 1Mb will be used."
        },
        {
            "flag": "-c",
            "long": null,
            "arg": null,
            "description": "Use the specified program to alert the operator when a media change is required. The alert program is typically a script to send a mail or flash a window to draw the opera‐ tor's attention."
        },
        {
            "flag": "-d",
            "long": null,
            "arg": null,
            "description": "Specifies the size, in megabytes, of dump media files. If not specified, xfsdump will dump data to tape using a single media file per media object. The specified media file size may need to be adjusted if, for example, xfsdump cannot fit a media file onto a single tape."
        },
        {
            "flag": "-e",
            "long": null,
            "arg": null,
            "description": "have the \"no dump\" file attribute set. See the \"Excluding individual files\" section be‐ low for details on setting this file attribute."
        },
        {
            "flag": "-f",
            "long": null,
            "arg": null,
            "description": "Specifies a dump destination. A dump destination can be the pathname of a device (such as a tape drive), a regular file or a remote tape drive (see rmt(8)). This option must be omitted if the standard output option (a lone - preceding the source filesystem spec‐ ification) is specified."
        },
        {
            "flag": "-l",
            "long": null,
            "arg": null,
            "description": "Specifies a dump level of 0 to 9. The dump level determines the base dump to which this dump is relative. The base dump is the most recent dump at a lesser level. A level 0 dump is absolute - all files are dumped. A dump level where 1 <= level <= 9 is referred to as an incremental dump. Only files that have been changed since the base dump are dumped. Subtree dumps (see the -s option below) cannot be used as the base for incre‐ mental dumps."
        },
        {
            "flag": "-m",
            "long": null,
            "arg": null,
            "description": "which are not scsi Linux tape drives nor IRIX tape drives. This option cannot be used without specifying a blocksize to be used (see -b option above)."
        },
        {
            "flag": "-o",
            "long": null,
            "arg": null,
            "description": "contents. This option may be used if xfsdump is unable to determine the block size of a tape ."
        },
        {
            "flag": "-p",
            "long": null,
            "arg": null,
            "description": "Causes progress reports to be printed at the specified interval. interval is given in seconds. The progress report indicates how many files have been dumped, the total num‐ ber of files to dump, the percentage of data dumped, and the elapsed time."
        },
        {
            "flag": "-q",
            "long": null,
            "arg": null,
            "description": "which xfsdump must make special allowances."
        },
        {
            "flag": "-s",
            "long": null,
            "arg": null,
            "description": "Restricts the dump to files contained in the specified pathnames (subtrees). A pathname must be relative to the mount point of the filesystem. For example, if a filesystem is mounted at /d2, the pathname argument for the directory /d2/users is ``users''. A path‐ name can be a file or a directory; if it is a directory, the entire hierarchy of files and subdirectories rooted at that directory is dumped. Subtree dumps cannot be used as the base for incremental dumps (see the -l option above)."
        },
        {
            "flag": "-t",
            "long": null,
            "arg": null,
            "description": "Sets the dump time to the modification time of file rather than using the current time. xfsdump uses the dump time to determine what files need to be backed up during an incre‐ mental dump. This option should be used when dumping snapshots so that the dump time matches the time the snapshot was taken. Otherwise files modified after a snapshot is taken may be skipped in the next incremental dump."
        },
        {
            "flag": "-v",
            "long": null,
            "arg": null,
            "description": ""
        },
        {
            "flag": "-v",
            "long": null,
            "arg": null,
            "description": "Specifies the level of detail used for messages displayed during the course of the dump. The verbosity argument can be passed as either a string or an integer. If passed as a string the following values may be used: silent, verbose, trace, debug, or nitty. If passed as an integer, values from 0-5 may be used. The values 0-4 correspond to the strings already listed. The value 5 can be used to produce even more verbose debug out‐ put. The first form of this option activates message logging across all dump subsystems. The second form allows the message logging level to be controlled on a per-subsystem basis. The two forms can be combined (see the example below). The argument subsys can take one of the following values: general, proc, drive, media, inventory, inomap and ex‐‐ cludedfiles. For example, to dump the root filesystem with tracing activated for all subsystems: # xfsdump -v trace -f /dev/tape / To enable debug-level tracing for drive and media operations: # xfsdump -v drive=debug,media=debug -f /dev/tape / To enable tracing for all subsystems, and debug level tracing for drive operations only: # xfsdump -v trace,drive=debug -f /dev/tape / To list files that will be excluded from the dump: # xfsdump -e -v excludedfiles=debug -f /dev/tape /"
        },
        {
            "flag": "-z",
            "long": null,
            "arg": null,
            "description": "Specifies the maximum size, in kilobytes, of files to be included in the dump. Files over this size, will be excluded from the dump, except for DMF dual-state files when '-a option' is specified (see '-a option' above). When specified, '-a option' takes prece‐ dence over '-z option'. The size is an estimate based on the number of disk blocks actu‐ ally used by the file, and so does not include holes. In other words, size refers to the amount of space the file would take in the resulting dump. On an interactive re‐ store, the skipped file is visible with xfsrestore's 'ls' and while you can use the 'add' and 'extract' commands, nothing will be restored."
        },
        {
            "flag": "-A",
            "long": null,
            "arg": null,
            "description": "environment this option should not be used. DMF stores file migration status within ex‐ tended attributes associated with each file. If these attributes are not preserved when the filesystem is restored, files that had been in migrated state will not be recallable by DMF. Note that dumps containing extended file attributes cannot be restored with older versions of xfsrestore(8)."
        },
        {
            "flag": "-B",
            "long": null,
            "arg": null,
            "description": "Specifies the ID of the dump session upon which this dump session is to be based. If this option is specified, the -l (level) and -R (resume) options are not allowed. In‐ stead, xfsdump determines if the current dump session should be incremental and/or re‐ sumed, by looking at the base session's level and interrupted attributes. If the base session was interrupted, the current dump session is a resumption of that base at the same level. Otherwise, the current dump session is an incremental dump with a level one greater than that of the base session. This option allows incremental and resumed dumps to be based on any previous dump, rather than just the most recent."
        },
        {
            "flag": "-D",
            "long": null,
            "arg": null,
            "description": "changed directories are dumped if files or directories beneath them have changed. This results in a self-contained dump -- if a base dump is lost, or you know the file(s) you wish to restore is in an incremental dump, you can restore just that dump without load‐ ing the base dump(s) first. However, this method requires a potentially expensive tra‐ versal through the filesystem. When -D is specified, unchanged directories are not dumped. This results in a faster dump, but files will end up in the xfsrestore(8) orphanage directory unless the base dump(s) is loaded first."
        },
        {
            "flag": "-E",
            "long": null,
            "arg": null,
            "description": "tor is prompted for confirmation, unless the -F option is also specified."
        },
        {
            "flag": "-F",
            "long": null,
            "arg": null,
            "description": "dump data, xfsdump normally asks the operator for permission to overwrite. With this option the overwrite is performed, no questions asked. When xfsdump encounters end-of- media during a dump, xfsdump normally asks the operator if another media object will be provided. With this option the dump is instead interrupted."
        },
        {
            "flag": "-I",
            "long": null,
            "arg": null,
            "description": "sion in an online inventory in /var/lib/xfsdump/inventory. xfsdump uses this inventory to determine the base for incremental dumps. It is also useful for manually identifying a dump session to be restored. Suboptions to filter the inventory display are described later."
        },
        {
            "flag": "-J",
            "long": null,
            "arg": null,
            "description": "to will be discarded or overwritten."
        },
        {
            "flag": "-K",
            "long": null,
            "arg": null,
            "description": "be restored on a system with an older xfsrestore which does not understand the current dump format. Use of this option is otherwise not recommended."
        },
        {
            "flag": "-L",
            "long": null,
            "arg": null,
            "description": "Specifies a label for the dump session. It can be any arbitrary string up to 255 char‐ acters long."
        },
        {
            "flag": "-M",
            "long": null,
            "arg": null,
            "description": "Specifies a label for the first media object (for example, tape cartridge) written on the corresponding destination during the session. It can be any arbitrary string up to 255 characters long. Multiple media object labels can be specified, one for each desti‐ nation."
        },
        {
            "flag": "-O",
            "long": null,
            "arg": null,
            "description": "Insert the options contained in optionsfile into the beginning of the command line. The options are specified just as they would appear if typed into the command line. In addition, newline characters (\\n) can be used as whitespace. The options are placed be‐ fore all options actually given on the command line, just after the command name. Only one -O option can be used. Recursive use is ignored. The source filesystem cannot be specified in optionsfile."
        },
        {
            "flag": "-R",
            "long": null,
            "arg": null,
            "description": "level (-l option) was interrupted, this dump contains only files not in the interrupted dump and consistent with the incremental level. However, files contained in the inter‐ rupted dump that have been subsequently modified are re-dumped."
        },
        {
            "flag": "-F",
            "long": null,
            "arg": null,
            "description": "prompts the operator for labels and media changes. Each dialogue normally times out if no response is supplied. This option prevents the timeout."
        },
        {
            "flag": "-Y",
            "long": null,
            "arg": null,
            "description": "Specify I/O buffer ring length. xfsdump uses a ring of output buffers to achieve maxi‐ mum throughput when dumping to tape drives. The default ring length is 3. However, this is not currently enabled on Linux yet, making this option benign. - A lone - causes the dump stream to be sent to the standard output, where it can be piped to another utility such as xfsrestore(8) or redirected to a file. This option cannot be used with the -f option. The - must follow all other options and precede the filesystem specification. The filesystem, filesystem, can be specified either as a mount point or as a special device file (for example, /dev/dsk/dks0d1s0). The filesystem must be mounted to be dumped."
        }
    ],
    "examples": [
        "To  perform  a  level  0, single stream dump of the root filesystem to a locally mounted tape",
        "drive, prompting for session and media labels when required:",
        "# xfsdump -f /dev/tape /",
        "To specify session and media labels explicitly:",
        "# xfsdump -L session1 -M tape0 -f /dev/tape /",
        "To perform a dump to a remote tape using the minimal rmt protocol and a set blocksize of 64k:",
        "# xfsdump -m -b 65536 -f otherhost:/dev/tape /",
        "To perform a level 0, multi-stream dump to two locally mounted tape drives:",
        "# xfsdump -L session2 -f /dev/rmt/tps4d6v -M tape1 \\",
        "-f /dev/rmt/tps5d6v -M tape2 /",
        "To perform a level 1 dump relative to the last level 0 dump recorded in the inventory:",
        "# xfsdump -l 1 -f /dev/tape /",
        "To copy the contents of a filesystem to another directory (see xfsrestore(8)):",
        "# xfsdump -J - / | xfsrestore -J - /new"
    ],
    "see_also": [
        {
            "name": "attr",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/attr/1/json"
        },
        {
            "name": "rmt",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/rmt/8/json"
        },
        {
            "name": "xfsrestore",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/xfsrestore/8/json"
        },
        {
            "name": "xfsinvutil",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/xfsinvutil/8/json"
        },
        {
            "name": "xfsquota",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/xfsquota/8/json"
        },
        {
            "name": "attrget",
            "section": "2",
            "url": "https://www.chedong.com/phpMan.php/man/attrget/2/json"
        }
    ]
}