mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-19 18:24:14 +08:00
4d66ea091a
Linux v3.20 was released as v4.0. Signed-off-by: Fanael Linithien <fanael4@gmail.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
351 lines
13 KiB
Plaintext
351 lines
13 KiB
Plaintext
|
|
The SGI XFS Filesystem
|
|
======================
|
|
|
|
XFS is a high performance journaling filesystem which originated
|
|
on the SGI IRIX platform. It is completely multi-threaded, can
|
|
support large files and large filesystems, extended attributes,
|
|
variable block sizes, is extent based, and makes extensive use of
|
|
Btrees (directories, extents, free space) to aid both performance
|
|
and scalability.
|
|
|
|
Refer to the documentation at http://oss.sgi.com/projects/xfs/
|
|
for further details. This implementation is on-disk compatible
|
|
with the IRIX version of XFS.
|
|
|
|
|
|
Mount Options
|
|
=============
|
|
|
|
When mounting an XFS filesystem, the following options are accepted.
|
|
For boolean mount options, the names with the (*) suffix is the
|
|
default behaviour.
|
|
|
|
allocsize=size
|
|
Sets the buffered I/O end-of-file preallocation size when
|
|
doing delayed allocation writeout (default size is 64KiB).
|
|
Valid values for this option are page size (typically 4KiB)
|
|
through to 1GiB, inclusive, in power-of-2 increments.
|
|
|
|
The default behaviour 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 behaviour.
|
|
|
|
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.
|
|
|
|
The default behaviour is determined by the on-disk feature
|
|
bit indicating that attr2 behaviour is active. If either
|
|
mount option it set, then that becomes the new default used
|
|
by the filesystem.
|
|
|
|
CRC enabled filesystems always use the attr2 format, and so
|
|
will reject the noattr2 mount option if it is set.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
filestreams
|
|
Make the data allocator use the filestreams allocation mode
|
|
across the entire filesystem rather than just on directories
|
|
configured to use it.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
|
|
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.
|
|
|
|
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 behaviour
|
|
is the same as if "nolargeio" was specified.
|
|
|
|
logbufs=value
|
|
Set the number of in-memory log buffers. Valid numbers
|
|
range from 2-8 inclusive.
|
|
|
|
The default value is 8 buffers.
|
|
|
|
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.
|
|
|
|
logbsize=value
|
|
Set the size of each in-memory log buffer. The size may be
|
|
specified in bytes, or in kilobytes with a "k" suffix.
|
|
Valid sizes for version 1 and version 2 logs are 16384 (16k)
|
|
and 32768 (32k). Valid sizes for version 2 logs also
|
|
include 65536 (64k), 131072 (128k) and 262144 (256k). The
|
|
logbsize must be an integer multiple of the log
|
|
stripe unit configured at mkfs time.
|
|
|
|
The default value for for version 1 logs is 32768, while the
|
|
default value for version 2 logs is MAX(32768, log_sunit).
|
|
|
|
logdev=device and 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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
noquota
|
|
Forcibly turns off all quota accounting and enforcement
|
|
within the filesystem.
|
|
|
|
uquota/usrquota/uqnoenforce/quota
|
|
User disk quota accounting enabled, and limits (optionally)
|
|
enforced. Refer to xfs_quota(8) for further details.
|
|
|
|
gquota/grpquota/gqnoenforce
|
|
Group disk quota accounting enabled and limits (optionally)
|
|
enforced. Refer to xfs_quota(8) for further details.
|
|
|
|
pquota/prjquota/pqnoenforce
|
|
Project disk quota accounting enabled and limits (optionally)
|
|
enforced. Refer to xfs_quota(8) for further details.
|
|
|
|
sunit=value and 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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
|
|
Deprecated Mount Options
|
|
========================
|
|
|
|
None at present.
|
|
|
|
|
|
Removed Mount Options
|
|
=====================
|
|
|
|
Name Removed
|
|
---- -------
|
|
delaylog/nodelaylog v4.0
|
|
ihashsize v4.0
|
|
irixsgid v4.0
|
|
osyncisdsync/osyncisosync v4.0
|
|
|
|
|
|
sysctls
|
|
=======
|
|
|
|
The following sysctls are available for the XFS filesystem:
|
|
|
|
fs.xfs.stats_clear (Min: 0 Default: 0 Max: 1)
|
|
Setting this to "1" clears accumulated XFS statistics
|
|
in /proc/fs/xfs/stat. It then immediately resets to "0".
|
|
|
|
fs.xfs.xfssyncd_centisecs (Min: 100 Default: 3000 Max: 720000)
|
|
The interval at which the filesystem flushes metadata
|
|
out to disk and runs internal cache cleanup routines.
|
|
|
|
fs.xfs.filestream_centisecs (Min: 1 Default: 3000 Max: 360000)
|
|
The interval at which the filesystem ages filestreams cache
|
|
references and returns timed-out AGs back to the free stream
|
|
pool.
|
|
|
|
fs.xfs.speculative_prealloc_lifetime
|
|
(Units: seconds Min: 1 Default: 300 Max: 86400)
|
|
The interval at which the background scanning for inodes
|
|
with unused speculative preallocation runs. The scan
|
|
removes unused preallocation from clean inodes and releases
|
|
the unused space back to the free pool.
|
|
|
|
fs.xfs.error_level (Min: 0 Default: 3 Max: 11)
|
|
A volume knob for error reporting when internal errors occur.
|
|
This will generate detailed messages & backtraces for filesystem
|
|
shutdowns, for example. Current threshold values are:
|
|
|
|
XFS_ERRLEVEL_OFF: 0
|
|
XFS_ERRLEVEL_LOW: 1
|
|
XFS_ERRLEVEL_HIGH: 5
|
|
|
|
fs.xfs.panic_mask (Min: 0 Default: 0 Max: 255)
|
|
Causes certain error conditions to call BUG(). Value is a bitmask;
|
|
OR together the tags which represent errors which should cause panics:
|
|
|
|
XFS_NO_PTAG 0
|
|
XFS_PTAG_IFLUSH 0x00000001
|
|
XFS_PTAG_LOGRES 0x00000002
|
|
XFS_PTAG_AILDELETE 0x00000004
|
|
XFS_PTAG_ERROR_REPORT 0x00000008
|
|
XFS_PTAG_SHUTDOWN_CORRUPT 0x00000010
|
|
XFS_PTAG_SHUTDOWN_IOERROR 0x00000020
|
|
XFS_PTAG_SHUTDOWN_LOGERROR 0x00000040
|
|
XFS_PTAG_FSBLOCK_ZERO 0x00000080
|
|
|
|
This option is intended for debugging only.
|
|
|
|
fs.xfs.irix_symlink_mode (Min: 0 Default: 0 Max: 1)
|
|
Controls whether symlinks are created with mode 0777 (default)
|
|
or whether their mode is affected by the umask (irix mode).
|
|
|
|
fs.xfs.irix_sgid_inherit (Min: 0 Default: 0 Max: 1)
|
|
Controls files created in SGID directories.
|
|
If the group ID of the new file does not match the effective group
|
|
ID or one of the supplementary group IDs of the parent dir, the
|
|
ISGID bit is cleared if the irix_sgid_inherit compatibility sysctl
|
|
is set.
|
|
|
|
fs.xfs.inherit_sync (Min: 0 Default: 1 Max: 1)
|
|
Setting this to "1" will cause the "sync" flag set
|
|
by the xfs_io(8) chattr command on a directory to be
|
|
inherited by files in that directory.
|
|
|
|
fs.xfs.inherit_nodump (Min: 0 Default: 1 Max: 1)
|
|
Setting this to "1" will cause the "nodump" flag set
|
|
by the xfs_io(8) chattr command on a directory to be
|
|
inherited by files in that directory.
|
|
|
|
fs.xfs.inherit_noatime (Min: 0 Default: 1 Max: 1)
|
|
Setting this to "1" will cause the "noatime" flag set
|
|
by the xfs_io(8) chattr command on a directory to be
|
|
inherited by files in that directory.
|
|
|
|
fs.xfs.inherit_nosymlinks (Min: 0 Default: 1 Max: 1)
|
|
Setting this to "1" will cause the "nosymlinks" flag set
|
|
by the xfs_io(8) chattr command on a directory to be
|
|
inherited by files in that directory.
|
|
|
|
fs.xfs.inherit_nodefrag (Min: 0 Default: 1 Max: 1)
|
|
Setting this to "1" will cause the "nodefrag" flag set
|
|
by the xfs_io(8) chattr command on a directory to be
|
|
inherited by files in that directory.
|
|
|
|
fs.xfs.rotorstep (Min: 1 Default: 1 Max: 256)
|
|
In "inode32" allocation mode, this option determines how many
|
|
files the allocator attempts to allocate in the same allocation
|
|
group before moving to the next allocation group. The intent
|
|
is to control the rate at which the allocator moves between
|
|
allocation groups when allocating extents for new files.
|
|
|
|
Deprecated Sysctls
|
|
==================
|
|
|
|
None at present.
|
|
|
|
|
|
Removed Sysctls
|
|
===============
|
|
|
|
Name Removed
|
|
---- -------
|
|
fs.xfs.xfsbufd_centisec v4.0
|
|
fs.xfs.age_buffer_centisecs v4.0
|