xfs_fstab - static information about filesystems (XFS extensions)
The file /etc/fstab describes the filesystems and swapping partitions used by the local machine. The system administrator can modify it with a text editor. It is read by commands that mount, unmount, and check the consis- tency of filesystems. The file consists of a number of lines of the form:
filesystem directory type options frequency pass
For example:
/dev/root / xfs rw 0 0
Fields are separated by white space; a `#' as the first non-white space character indicates a comment.
The mnt_dir field is the full pathname of the directory to be mounted on. The mnt_type field determines how the mnt_fsname and mnt_opts fields are interpreted. Here is a list of the filesystem types currently supported, and the way each of them interprets these fields:
xfs mnt_fsname must be a block special device (for example, /dev/root) or a logical volume. mnt_freq is
not used in current IRIX systems.
mnt_passno can be used to control the behavior of parallel filesystem checking on bootup, see fsck(1M).
The mnt_opts field contains a list of comma-separated option words. Some mnt_opts are valid for all filesystem types, while others apply to a specific type only.
Options specific to xfs filesystems are:
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quota biosize |
Disk quota accounting enabled, and limits enforced. The biosize (buffered I/O size) option can be used to set the default preferred buffered I/O size for filesystem. The default preferred I/O size is 64K. The biosize option can be used to decrease the pre- ferred I/O size. The size must be expressed as the log (base2) of the desired I/O size. Valid values for this option are 14 through 16, inclusive (e.g. 16K, 32K, and 64K bytes). On machines with 4K size pages, 13 (8 Kbytes) is also a valid size. The preferred buffered I/O size can also be altered on a per-file basis using the fcntl system call. See fcntl(2) for further details. |
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dmi logbufs |
Enable the Data Management Interface event callouts. Set the number of in memory log buffers. Valid numbers range from 2-8 inclusive. The default value is 8 buffers for filesystems with a blocksize of 64K, 4 buffers for filesystems with a blocksize of 32K, 3 buffers for filesystems with a blocksize of 16K, and 2 buffers for all other configurations. Increasing the number of buffers may increase performance on some workloads at the cost of the memory used for the extra log buffers and their associated control structures. |
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noalign noatime |
Data allocations will not be aligned at stripe unit boundaries. Access timestamps are not updated when a file is read. |
norecovery
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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. |
osyncisdsync
Make writes to files opened with the O_SYNC flag set behave as if the O_DSYNC flag had been used
instead. This can result in better performance without compromising data safety. However if this
option in effect, timestamp updates from O_SYNC writes can be lost if the system crashes.
Disk quota accounting enabled, but limits are not enforced.
pquota Project disk quota accounting enabled and limits enforced.
Project disk quota accounting enabled, but limits are not enforced.
sunit=value
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Used to specify the stripe unit for a RAID device or a xlv stripe volume. value has to be specified in 512-byte block units. If this option is not specified and the filesystem was made on a stripe volume or the stripe unit was specified for the RAID device at mkfs time, then the mount system call will restore the value from the superblock. For filesystems that are made directly on RAID devices, this option can be used to override the information in the superblock if the underlying disk layout changes after the |
filesystem has been mkfsed. If the filesystem is made on a xlv volume, then this will be done implicitly.
swidth=value
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Used to specify the stripe width for a RAID device or a xlv stripe volume. value has to be specified in 512-byte block units. If this option is not specified, and the filesystem was made on a stripe volume or the stripe width was specified for the RAID device at mkfs time, then the mount system call will restore the value from the superblock. For filesystems that are made directly on RAID devices, this option can be used to override the information in the superblock if the underlying disk layout changes after the filesystem has been mkfsed. If the filesystem is made on a xlv volume, then this will be done implicitly. This option is required if the -o sunit option has been specified. Also it has to be a multiple of the sunit option. |
wsync All operations that modify the filesystem are synchronous except for writes to user files (e.g. create,
unlink, mv, truncate, etc.). This option can be used in conjunction with exporting a filesystem -wsync to
obtain NFS write-synchronous semantics, if so desired. See exports(5) for further information.
/etc/fstab
xfs(5).