# xfs_admin

## NAME



           xfs_admin - change parameters of an XFS filesystem
    


## SYNOPSIS



           **xfs_admin**[ **-eflpu**] [ **-O** _featurelist_ ] [ **-c 0** |**1**] [ **-L** _label_ ] [
           **-U** _uuid_ ] [ **-r** _rtdev_ ] _device_ [ _logdev_ ]
           **xfs_admin -V**
    


## DESCRIPTION



           **xfs_admin** uses the xfs_db(8) 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) can convert
           parameters.  A number of parameters of a mounted filesystem can be
           examined and modified using the xfs_growfs(8) command.
    
           The optional **logdev** parameter specifies the device special file
           where the filesystem's external log resides.  This is required
           only for filesystems that use an external log.  See the **mkfs.xfs**
           **-l** option, and refer to xfs(5) for a detailed description of the
           XFS log.
    


## OPTIONS



           **-e** Enables unwritten extent support on a filesystem that does
                  not already have this enabled (for legacy filesystems, it
                  can't be disabled anymore at mkfs time).
    
                  This option only applies to the deprecated V4 format.
    
           **-f** Specifies that the filesystem image to be processed is
                  stored in a regular file at _device_ (see the **mkfs.xfs -d**
                  _file_ option).
    
           **-j** Enables version 2 log format (journal format supporting
                  larger log buffers).
    
                  This option only applies to the deprecated V4 format.
    
           **-l** Print the current filesystem label.
    
           **-p** Enable 32bit project identifier support (PROJID32BIT
                  feature).
    
                  This option only applies to the deprecated V4 format.
    
           **-u** Print the current filesystem UUID (Universally Unique
                  IDentifier).
    
           **-c 0** |**1** Enable (1) or disable (0) lazy-counters in the filesystem.
    
                  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** _label_
                  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** _feature1_**=**_status_**,**_feature2_**=**_status..._
                  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, recovery
                  procedures (e.g. reformat followed by restoration from
                  backup; or running **xfs_repair** 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 enabled. Once enabled, the
                      filesystem will not be mountable by older kernels.
                      This feature was added to Linux 5.19.
    
                  **exchange**
                      Upgrade a filesystem to support atomic file content
                      exchanges through the XFS_IOC_EXCHANGE_RANGE ioctl, and
                      to support online repairs of directories, extended
                      attributes, symbolic links, and realtime free space
                      metadata.  The filesystem cannot be downgraded after
                      this feature is enabled.  Once enabled, the filesystem
                      will not be mountable by older kernels.
    
           **-U** _uuid_
                  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** _rtdev_
                  Specifies the device special file where the filesystem's
                  realtime section resides.  Only for those filesystems which
                  use a realtime section.
    
           **-V** Prints the version number and exits.
    
           The mount(8) manual entry describes how to mount a filesystem
           using its label or UUID, rather than its block special device
           name.
    


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