None.
.SH "Mount options for xfs"
-.TP
-.BI allocsize= size
-Sets the buffered I/O end-of-file preallocation size when
-doing delayed allocation writeout. Valid values for this
-option are page size (typically 4KiB) through to 1GiB,
-inclusive, in power-of-2 increments.
-.sp
-The default behavior is for dynamic end-of-file
-preallocation size, which uses a set of heuristics to
-optimise the preallocation size based on the current
-allocation patterns within the file and the access patterns
-to the file. Specifying a fixed allocsize value turns off
-the dynamic behavior.
-.TP
-.BR attr2 | noattr2
-The options enable/disable an "opportunistic" improvement to
-be made in the way inline extended attributes are stored
-on-disk. When the new form is used for the first time when
-attr2 is selected (either when setting or removing extended
-attributes) the on-disk superblock feature bit field will be
-updated to reflect this format being in use.
-.sp
-The default behavior is determined by the on-disk feature
-bit indicating that attr2 behavior is active. If either
-mount option it set, then that becomes the new default used
-by the filesystem.
-.sp
-CRC enabled filesystems always use the attr2 format, and so
-will reject the noattr2 mount option if it is set.
-.TP
-.BR barrier | nobarrier
-Enables/disables the use of block layer write barriers for
-writes into the journal and for data integrity operations.
-This allows for drive level write caching to be enabled, for
-devices that support write barriers.
-.TP
-.BR discard | nodiscard
-Enable/disable the issuing of commands to let the block
-device reclaim space freed by the filesystem. This is
-useful for SSD devices, thinly provisioned LUNs and virtual
-machine images, but may have a performance impact.
-.sp
-Note: It is currently recommended that you use the fstrim
-application to discard unused blocks rather than the discard
-mount option because the performance impact of this option
-is quite severe.
-.TP
-.BR grpid | bsdgroups | nogrpid | sysvgroups
-These options define what group ID a newly created file
-gets. When grpid is set, it takes the group ID of the
-directory in which it is created; otherwise it takes the
-fsgid of the current process, unless the directory has the
-setgid bit set, in which case it takes the gid from the
-parent directory, and also gets the setgid bit set if it is
-a directory itself.
-.TP
-.B filestreams
-Make the data allocator use the filestreams allocation mode
-across the entire filesystem rather than just on directories
-configured to use it.
-.TP
-.BR ikeep | noikeep
-When ikeep is specified, XFS does not delete empty inode
-clusters and keeps them around on disk. When noikeep is
-specified, empty inode clusters are returned to the free
-space pool.
-.TP
-.BR inode32 | inode64
-When inode32 is specified, it indicates that XFS limits
-inode creation to locations which will not result in inode
-numbers with more than 32 bits of significance.
-.sp
-When inode64 is specified, it indicates that XFS is allowed
-to create inodes at any location in the filesystem,
-including those which will result in inode numbers occupying
-more than 32 bits of significance.
-.sp
-inode32 is provided for backwards compatibility with older
-systems and applications, since 64 bits inode numbers might
-cause problems for some applications that cannot handle
-large inode numbers. If applications are in use which do
-not handle inode numbers bigger than 32 bits, the inode32
-option should be specified.
-.TP
-.BR largeio | nolargeio
-If "nolargeio" is specified, the optimal I/O reported in
-st_blksize by stat(2) will be as small as possible to allow
-user applications to avoid inefficient read/modify/write
-I/O. This is typically the page size of the machine, as
-this is the granularity of the page cache.
-.sp
-If "largeio" specified, a filesystem that was created with a
-"swidth" specified will return the "swidth" value (in bytes)
-in st_blksize. If the filesystem does not have a "swidth"
-specified but does specify an "allocsize" then "allocsize"
-(in bytes) will be returned instead. Otherwise the behavior
-is the same as if "nolargeio" was specified.
-.TP
-.BI logbufs= value
-Set the number of in-memory log buffers. Valid numbers
-range from 2\(en8 inclusive.
-.sp
-The default value is 8 buffers.
-.sp
-If the memory cost of 8 log buffers is too high on small
-systems, then it may be reduced at some cost to performance
-on metadata intensive workloads. The logbsize option below
-controls the size of each buffer and so is also relevant to
-this case.
-.TP
-.BI logbsize= value
-Set the size of each in-memory log buffer. The size may be
-specified in bytes, or in kibibytes (KiB) with a "k" suffix.
-Valid sizes for version 1 and version 2 logs are 16384 (value=16k)
-and 32768 (value=32k). Valid sizes for version 2 logs also
-include 65536 (value=64k), 131072 (value=128k) and 262144 (value=256k).
-The logbsize must be an integer multiple of the log
-stripe unit configured at mkfs time.
-.sp
-The default value for version 1 logs is 32768, while the
-default value for version 2 logs is MAX(32768, log_sunit).
-.TP
-.BI logdev= "device \fRand " rtdev= device
-Use an external log (metadata journal) and/or real-time device.
-An XFS filesystem has up to three parts: a data section, a log
-section, and a real-time section. The real-time section is
-optional, and the log section can be separate from the data
-section or contained within it.
-.TP
-.B noalign
-Data allocations will not be aligned at stripe unit
-boundaries. This is only relevant to filesystems created
-with non-zero data alignment parameters (sunit, swidth) by
-mkfs.
-.TP
-.B norecovery
-The filesystem will be mounted without running log recovery.
-If the filesystem was not cleanly unmounted, it is likely to
-be inconsistent when mounted in "norecovery" mode.
-Some files or directories may not be accessible because of this.
-Filesystems mounted "norecovery" must be mounted read-only or
-the mount will fail.
-.TP
-.B nouuid
-Don't check for double mounted file systems using the file
-system uuid. This is useful to mount LVM snapshot volumes,
-and often used in combination with "norecovery" for mounting
-read-only snapshots.
-.TP
-.B noquota
-Forcibly turns off all quota accounting and enforcement
-within the filesystem.
-.TP
-.B uquota/usrquota/uqnoenforce/quota
-User disk quota accounting enabled, and limits (optionally)
-enforced. Refer to xfs_quota(8) for further details.
-.TP
-.B gquota/grpquota/gqnoenforce
-Group disk quota accounting enabled and limits (optionally)
-enforced. Refer to xfs_quota(8) for further details.
-.TP
-.B pquota/prjquota/pqnoenforce
-Project disk quota accounting enabled and limits (optionally)
-enforced. Refer to xfs_quota(8) for further details.
-.TP
-.BI sunit= "value \fRand " swidth =value
-Used to specify the stripe unit and width for a RAID device
-or a stripe volume. "value" must be specified in 512-byte
-block units. These options are only relevant to filesystems
-that were created with non-zero data alignment parameters.
-.sp
-The sunit and swidth parameters specified must be compatible
-with the existing filesystem alignment characteristics. In
-general, that means the only valid changes to sunit are
-increasing it by a power-of-2 multiple. Valid swidth values
-are any integer multiple of a valid sunit value.
-.sp
-Typically the only time these mount options are necessary if
-after an underlying RAID device has had it's geometry
-modified, such as adding a new disk to a RAID5 lun and
-reshaping it.
-.TP
-.B swalloc
-Data allocations will be rounded up to stripe width boundaries
-when the current end of file is being extended and the file
-size is larger than the stripe width size.
-.TP
-.B wsync
-When specified, all filesystem namespace operations are
-executed synchronously. This ensures that when the namespace
-operation (create, unlink, etc) completes, the change to the
-namespace is on stable storage. This is useful in HA setups
-where failover must not result in clients seeing
-inconsistent namespace presentation during or after a
-failover event.
+See the options section of the
+.BR xfs (5)
+man page (xfsprogs package must be installed).
.SH "THE LOOP DEVICE"
One further possible type is a mount via the loop device. For example,
projects / thirdparty / util-linux.git / commitdiff
