fsck - check and repair file systems
fsck [-F FSType] [-m] [-V] [special...]
fsck [-F FSType] [-n | N | y | Y] [-V] [-o FSType-specific-options] [special...]
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 cor-
rective 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 spe-
cial 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(1M)) for more information.
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 appropri-
ate 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.
-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).
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(1M) with the -Nv options specified.
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 inter-
action. 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(1M). 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.
Force checking of file systems regardless of the state of their super block clean flag.
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.
Check writable file systems only.
0 file system is okay and does not need checking
1 erroneous parameters are specified
32 file system is unmounted and needs checking (fsck -monly)
33 file system is already mounted
34 cannot stat device
36 uncorrectable errors detected - terminate normally
37 a signal was caught during processing
39 uncorrectable errors detected - terminate immediately
40 for root, same as 0.
See largefile(5) for the description of the behavior of fsck when encountering files greater than or equal to 2 Gbyte (2**31 bytes).
/etc/default/fs default local file system type. Default values can be set for the following flags in /etc/default/fs. For example:
LOCAL The default partition for a command if no FSType is specified.
/etc/vfstab list of default parameters for each file system
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|Availability |SUNWcsu |
clri(1M), fsck_cachefs(1M), fsck_ufs(1M), fsdb_ufs(1M), fsirand(1M), fstyp(1M), mkfs(1M), mkfs_ufs(1M), mountall(1M), newfs(1M), reboot(
1M), vfstab(4), attributes(5), largefile(5), ufs(7FS)
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.
This command may not be supported for all FSTypes.
Running fsck on file systems larger than 2 Gb fails if the user chooses to use the block interface to the device:
rather than the raw (character special) device:
Starting with Solaris 9, fsck manages extended attribute data on the disk. (See fsattr(5) 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
18 July 2004 fsck(1M)