# xfs_admin - change parameters of an XFS filesystem - man(8) - [phpMan] [_xfs_admin_(8)](https://www.chedong.com/phpMan.php/man/xfsadmin/8/markdown) System Manager's Manual [_xfs_admin_(8)](https://www.chedong.com/phpMan.php/man/xfsadmin/8/markdown) ## NAME xfs_admin - change parameters of an XFS filesystem ## SYNOPSIS **xfs_admin **[ **-eflpu **] [ **-O _**featurelist_ ] [ **-c 0**|**1 **] [ **-L _**label_ ] [ **-U _**uuid_ ] [ **-r _**rtdev_ ] _de‐_ _vice_ [ _logdev_ ] ### xfs_admin -V ## DESCRIPTION **xfs_admin **uses the [**xfs_db**(8)](https://www.chedong.com/phpMan.php/man/xfsdb/8/markdown) command to modify various parameters of a filesystem. Devices that are mounted cannot be modified. Administrators must unmount filesystems before **xfs_admin **or [**xfs_db**(8)](https://www.chedong.com/phpMan.php/man/xfsdb/8/markdown) can convert parameters. A number of parameters of a mounted filesys‐ tem can be examined and modified using the [**xfs_growfs**(8)](https://www.chedong.com/phpMan.php/man/xfsgrowfs/8/markdown) command. The optional **logdev **parameter specifies the device special file where the filesystem's exter‐ nal log resides. This is required only for filesystems that use an external log. See the **mkfs.xfs -l **option, and refer to [**xfs**(5)](https://www.chedong.com/phpMan.php/man/xfs/5/markdown) for a detailed description of the XFS log. ## OPTIONS ### -e abled (for legacy filesystems, it can't be disabled anymore at mkfs time). This option only applies to the deprecated V4 format. ### -f _vice_ (see the **mkfs.xfs -d _**file_ option). ### -j This option only applies to the deprecated V4 format. ### -l ### -p This option only applies to the deprecated V4 format. ### -u ### -c 0 Lazy-counters may not be disabled on Version 5 superblock filesystems (i.e. those with metadata CRCs enabled). In other words, this option only applies to the deprecated V4 format. This operation may take quite a bit of time on large filesystems as the entire filesystem needs to be scanned when this option is changed. With lazy-counters enabled, the superblock is not modified or logged on every change of the free-space and inode counters. Instead, enough information is kept in other parts of the filesystem to be able to maintain the counter values without needing to keep them in the superblock. This gives significant improvements in performance on some configurations and metadata intensive workloads. ### -L _ Set the filesystem label to _label_. XFS filesystem labels can be at most 12 characters long; if _label_ is longer than 12 characters, **xfs_admin **will truncate it and print a warning message. The filesystem label can be cleared using the special "**--**" value for _label_. ### -O _ Add or remove features on an existing V5 filesystem. The features should be specified as a comma-separated list. _status_ should be either 0 to disable the feature or 1 to enable the feature. Note, however, that most features cannot be disabled. **NOTE: **Administrators must ensure the filesystem is clean by running **xfs_repair -n **to inspect the filesystem before performing the upgrade. If corruption is found, recov‐ ery procedures (e.g. reformat followed by restoration from backup; or running **xfs_re‐** **pair **without the **-n**) must be followed to clean the filesystem. Supported features are as follows: **inobtcount** Keep a count the number of blocks in each inode btree in the AGI. This reduces mount time by speeding up metadata space reservation calculations. The filesystem cannot be downgraded after this feature is enabled. Once enabled, the filesystem will not be writable by older kernels. This feature was added to Linux 5.10. **bigtime** Upgrade a filesystem to support larger timestamps up to the year 2486. The filesystem cannot be downgraded after this feature is enabled. Once enabled, the filesystem will not be mountable by older kernels. This feature was added to Linux 5.10. **nrext64** Upgrade a filesystem to support large per-inode extent counters. The maximum data fork extent count will be 2^48 - 1, while the maximum attribute fork extent count will be 2^32 - 1. The filesystem cannot be downgraded after this feature is en‐ abled. Once enabled, the filesystem will not be mountable by older kernels. This feature was added to Linux 5.19. ### -U _ Set the UUID of the filesystem to _uuid_. A sample UUID looks like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The _uuid_ may also be **nil**, which will set the filesystem UUID to the null UUID. The _uuid_ may also be **generate**, which will generate a new UUID for the filesystem. Note that on CRC-enabled filesystems, this will set an incompatible flag such that older kernels will not be able to mount the filesystem. To remove this incompatible flag, use **restore**, which will restore the original UUID and remove the incompatible feature flag as needed. ### -r _ Specifies the device special file where the filesystem's realtime section resides. Only for those filesystems which use a realtime section. ### -V The [**mount**(8)](https://www.chedong.com/phpMan.php/man/mount/8/markdown) manual entry describes how to mount a filesystem using its label or UUID, rather than its block special device name. ## SEE ALSO [**mkfs.xfs**(8)](https://www.chedong.com/phpMan.php/man/mkfs.xfs/8/markdown), [**mount**(8)](https://www.chedong.com/phpMan.php/man/mount/8/markdown), [**xfs_db**(8)](https://www.chedong.com/phpMan.php/man/xfsdb/8/markdown), [**xfs_growfs**(8)](https://www.chedong.com/phpMan.php/man/xfsgrowfs/8/markdown), [**xfs_repair**(8)](https://www.chedong.com/phpMan.php/man/xfsrepair/8/markdown), [**xfs**(5)](https://www.chedong.com/phpMan.php/man/xfs/5/markdown). [_xfs_admin_(8)](https://www.chedong.com/phpMan.php/man/xfsadmin/8/markdown)