fsck(1M) fsck(1M)
NAME
fsck (generic) - check and repair file systems
SYNOPSIS
fsck [-F FSType] [-V] [-m] [special ...]
fsck [-F FSType] [genericoptions] [-o specificoptions] [special ...]
DESCRIPTION
fsck audits and interactively repairs inconsistent conditions for file
systems. If the file system is inconsistent the user is prompted for
concurrence before each correction is attempted. It should be noted
that some corrective actions will result in some loss of data. The
amount and severity of data loss may be determined from the diagnostic
output. The default action for each correction is to wait for the user
to respond "yes" or "no". If the user does not have write permission
fsck defaults to a "no" action.
The file system should be unmounted when fsck is used. If this is not
possible, care should be taken that the system is quiescent and that
it is rebooted immediately afterwards if the file system is essential
for the boot process.
special represents a block or character special device (e.g.
/dev/ios0/rsdisk000s8). It is preferable that a character special
device be used. fsck will not work on a block device if it is mounted.
If special is not supplied, fsck looks through /etc/vfstab and exe-
cutes fsck for all character specials in the "fsckdev" field of
/etc/vfstab for which there is a numeric entry in the "fsckpass" field
[see vfstab(4)].
If the -p option is given and no special devices are present, then
fsck will preen the file system. In this case, fsck will use the
information gathered from /etc/vfstab to inspect groups of disks in
parallel to take maximum advantage of I/O overlap when checking the
file systems. This causes fsck to run as quickly as possible. If the
-s option is used in conjunction with the -p option, fsck will inspect
the following specified number of filesystems per disk spindle. If the
-s option is not used, fsck with the -p option defaults to inspecting
up to 2 filesystems per disk spindle.
Note: If disks are to be checked in parallel, the entry in the
"fsckpass" field in /etc/vfstab for those disks to be checked
in parallel is to be set to the same value >=1.
If sent a QUIT signal, fsck will finish the file system checks, then
exit with an abnormal return status. This is intended to cause an
automatic reboot to fail, giving control back to the user.
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fsck(1M) fsck(1M)
OPTIONS
There are three types of option: genericoptions, otheroptions and
specificoptions.
genericoptions Indicate options that are supported not only by the
generic but also by the FST-specific module of the
command (if that command exists).
otheroptions Indicate options that are supported only by the gen-
eric command.
specificoptions Indicate suboptions that are supported only by the
FSType-specific module [see fsck(1M-ufs) or
fsck(1M-vxfs)] of the command. They are specified in
a comma-separated list and/or as keyword-attribute
pairs for interpretation by the FSType-specific
module of the command. These suboptions are speci-
fied via the -o option.
The genericoptions are:
-F FSType
Specifies the file system type on which to operate on the given
special device. If no special devices are given, then fsck will
restrict its checks to file systems of that FSType.
The FSType should either be specified here or be determinable
from /etc/vfstab by matching the special with an entry in the
table. For legal FSTypes see df(1).
-V Echoes the complete command line, but does not execute the com-
mand. The command line is generated by using the options and
arguments provided by the user and adding to them information
derived from /etc/vfstab. This option should be used to verify
and validate the command line. When used with the FSType option,
it passes the -V to the FSType-specific module for interpreta-
tion.
-I Insists that a file system be checked. This forces fsck to ignore
the state of the file system and perform the consistency checks.
-y Assumes a yes response to all questions asked by fsck.
-n Assumes a no response to all questions asked by fsck.
-p Checks the file system in preen mode. Correct inconsistencies that
can be fixed automatically, that is, inconsistencies that are
deemed harmless and can be fixed without confirmation by the
administrator. Examples of such inconsistencies are unreferenced
i-nodes, incorrect counts in the superblocks, and missing blocks in
the free list. If given without arguments, this option will sort
all file systems that are to be checked for efficient throughput.
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fsck(1M) fsck(1M)
-s Specifies the number of filesystems to be inspected simultane-
ously per disk spindle. This option is only used with the -p
option. By default, fsck with the -p option will inspect up to
two filesystems per disk spindle at the same time. This can lead
to degraded performance, however, if the filesystems are physi-
cally separated on the disk medium due to the cost of seeking.
Valid values for the number of filesystems to inspect are 1
through 4.
-l level
Limits the action to file systems at a specified level. Legal
levels are 0 through 9 and u:
Level 0: Essential file systems for boot process (such as
/usr, /var)
Level 1-9: Other file systems.
Level u: Check all levels except level 0.
-o Specifies FSType-specific options.
The otheroptions are:
-m Check but don't repair. This option checks that the file system
is suitable for mounting.
NOTES
This command may not be supported for all FSTypes.
Certain utilities can cause a file system to be marked consistent when
they are not. For example, unlink, clri, mvdir, and fsdb were designed
to structurally modify the file system components at a low level, and
so do not update any of the file system resource allocation maps or
other related information. Consequently, use of these commands may
leave a file system inconsistent, even when it is not marked as such.
Any file system that is altered using one of these commands should
always be checked using the -I option.
FILES
/etc/vfstab
list of default parameters for each file system
SEE ALSO
df(1), mkfs(1M), vfstab(4).
FSType-specific modules: fsck(1M-ufs), fsck(1M-vxfs). Online call
e.g.: "man 1M-ufs fsck".
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