FSCK(8) Maintenance Commands and Procedures FSCK(8)

NAME

fsck - check and repair file systems

SYNOPSIS

fsck [-F FSType] [-m] [-V] [-v] [special]...


fsck [-F FSType] [-n | N | y | Y] [-V] [-v]
[-o FSType-specific-options] [special]...

DESCRIPTION

fsck audits and interactively repairs inconsistent file system
conditions. If the file system is inconsistent 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.
Some corrective actions will result in loss of data. The amount and
severity of data loss can be determined from the diagnostic output.


FSType-specific-options are options specified in a comma-separated
(with no intervening spaces) list of options or keyword-attribute
pairs for interpretation by the FSType-specific module of the
command.


special represents the character special device on which the file
system resides, for example, /dev/rdsk/c1t0d0s7. Note: the character
special device, not the block special device, should be used. fsck
will not work if the block device is mounted.


If no special device is specified fsck checks the file systems listed
in /etc/vfstab. Those entries in /etc/vfstab which have a character
special device entry in the fsckdev field and have a non-zero numeric
entry in the fsckpass field will be checked. Specifying -F FSType
limits the file systems to be checked to those of the type indicated.


If special is specified, but -F is not, the file system type will be
determined by looking for a matching entry in /etc/vfstab. If no
entry is found, the default local file system type specified in
/etc/default/fs will be used.


If a file system type supports parallel checking, for example, ufs,
some file systems eligible for checking may be checked in parallel.
Consult the file system-specific man page (for example, fsck_ufs(8))
for more information.

OPTIONS

The following generic options are supported:

-F FSType

Specify the file system type on which to operate.


-m

Check but do not repair. This option checks that the file system
is suitable for mounting, returning the appropriate exit status.
If the file system is ready for mounting, fsck displays a message
such as:

ufs fsck: sanity check: /dev/rdsk/c0t3d0s1 okay


-n | -N

Assume a no response to all questions asked by fsck; do not open
the file system for writing.


-V

Echo the expanded command line but do not execute the command.
This option may be used to verify and to validate the command
line.


-v

Enables verbose output. Might not be supported by all filesystem-
specific fsck implementations.


-y | Y

Assume a yes response to all questions asked by fsck.


-o specific-options

These specific-options can be any combination of the following
separated by commas (with no intervening spaces).

b=n

Use block n as the super block for the file system. Block 32
is always one of the alternate super blocks. Determine the
location of other super blocks by running newfs(8) with the
-Nv options specified.


c

If the file system is in the old (static table) format,
convert it to the new (dynamic table) format. If the file
system is in the new format, convert it to the old format
provided the old format can support the file system
configuration. In interactive mode, fsck will list the
direction the conversion is to be made and ask whether the
conversion should be done. If a negative answer is given, no
further operations are done on the file system. In preen
mode, the direction of the conversion is listed and done if
possible without user interaction. Conversion in preen mode
is best used when all the file systems are being converted at
once. The format of a file system can be determined from the
first line of output from fstyp(8). Note: the c option is
seldom used and is included only for compatibility with
pre-4.1 releases. There is no guarantee that this option will
be included in future releases.


f

Force checking of file systems regardless of the state of
their super block clean flag.


p

Check and fix the file system non-interactively ("preen").
Exit immediately if there is a problem requiring
intervention. This option is required to enable parallel file
system checking.


w

Check writable file systems only.

EXIT STATUS

0

file system is unmounted and OK


1

erroneous parameters are specified


32

file system is unmounted and needs checking (fsck -m only)


33

file system is already mounted


34

cannot stat device


35

a filesystem that is mounted read/write was modified - reboot


36

uncorrectable errors detected - terminate normally


37

a signal was caught during processing


39

uncorrectable errors detected - terminate immediately


40

file system is mounted read-only and is OK

USAGE

The fsck command is large file aware for UFS file systems, per the
largefile(7) man page.

FILES

/etc/default/fs

default local file system type. Default values can be set for the
following flags in /etc/default/fs. For example: LOCAL=ufs.

LOCAL

The default partition for a command if no FSType is
specified.


/etc/vfstab

list of default parameters for each file system

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Committed |
+--------------------+-----------------+

SEE ALSO

ufs(4FS), vfstab(5), attributes(7), largefile(7), clri(8),
fsck_ufs(8), fsdb_ufs(8), fsirand(8), fstyp(8), mkfs(8), mkfs_ufs(8),
mountall(8), newfs(8), reboot(8)

WARNINGS

The operating system buffers file system data. Running fsck on a
mounted file system can cause the operating system's buffers to
become out of date with respect to the disk. For this reason, 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 after fsck is run. Quite often, however,
this will not be sufficient. A panic will probably occur if running
fsck on a file system modifies the file system.

NOTES

This command may not be supported for all FSTypes.

Starting with Solaris 9, fsck manages extended attribute data on the
disk. (See fsattr(7) for a description of extended file attributes.)
A file system with extended attributes can be mounted on versions of
Solaris that are not attribute-aware (versions prior to Solaris 9),
but the attributes will not be accessible and fsck will strip them
from the files and place them in lost+found. Once the attributes have
been stripped, the file system is completely stable on versions of
Solaris that are not attribute-aware, but would be considered
corrupted on attribute-aware versions. In the latter circumstance,
run the attribute-aware fsck to stabilize the file system before
using it in an attribute-aware environment.

September 8, 2015 FSCK(8)