fsck_hfs.1m (2010 09)

f
fsck_hfs(1M) fsck_hfs(1M)
NAME
fsck_hfs: fsck - HFS file system consistency check and interactive repair
SYNOPSIS
/usr/sbin/fsck
[-F hfs][-m][-i][
-s][-V][-b blocknum][special ]...
/usr/sbin/fsck
[-F hfs][-c size][-f
][-i][-p-P][-V][-s][special ]...
/usr/sbin/fsck
[-F hfs][-b blocknum][-c size][
-f][-i][-n-N-y-Y]
[
-q][-s][-V
][special ]...
DESCRIPTION
The
fsck command audits and repairs inconsistent conditions for HFS file systems on mass storage dev-
ice files identified by special . If the file system is consistent, the number of files on that file system and
the number of used and free blocks are reported. If the file system is inconsistent,
fsck provides a
mechanism to fix these inconsistencies, depending on which form of the
fsck command is used.
special represents a special device (for example,
/dev/rdisk/disk8).
If the target device is a swap device,
fsck does not continue to process. fsck also checks the target dev-
ice to ensure a mounted file system is not being checked. If a mounted device is specified but the
-f and
-i options are omitted, fsck prompts the user for a response.
If the
-p-P option is used and special is not specified, fsck reads the pass numbers in
/etc/fstab
to determine which groups of disks to inspect in parallel, taking maximum advantage of I/O overlap to
process the file systems as quickly as possible. The -p-P option is normally used in the script
/sbin/bcheckrc during automatic reboot.
Normally, the root file system is checked on pass 1, and other "root" (section 0) file systems on pass 2.
Other small file systems are checked on separate passes (such as the section 4 file systems on pass 3 and
the section 7 file systems on pass 4), and finally the large user file systems are checked on the last pass
(for example, pass 5). A pass number of 0 in
/etc/fstab causes a file system not to be checked. If the
optional fields are not present on a line in /etc/fstab, fsck processes the file system on such lines
sequentially after all eligible file systems with positive pass numbers have been processed.
The inconsistencies that
fsck with the -p-P option corrects are shown below. These are inconsisten-
cies that are correctable without data loss. If it encounters other inconsistencies, it exits with an abnor-
mal return status. For each corrected inconsistency, one or more lines are printed identifying the file sys-
tem on which the correction will take place and the nature of the correction. Correctable inconsistencies
are limited to the following:
• Unreferenced inodes
• Unreferenced continuation inodes
• Unreferenced pipes and FIFOs
• Link counts in inodes too large
• Missing blocks in the free list
• Blocks in the free list also in files
• Counts in the superblock wrong.
The
-P option operates in the same manner as the -p option except that cleanly unmounted file systems
are not checked (see fsclean (1M)). This can greatly decrease the amount of time required to reboot a sys-
tem that was brought down cleanly.
If the
-p-P option is not specified, the pass numbers are ignored and the file systems are checked
interactively in the order they are listed in /etc/fstab.
Without the
-p-P option, fsck prompts for concurrence before each correction is attempted when the
file system is inconsistent. It should be noted that some corrective actions result in a loss of data. The
amount and severity of data loss can be determined from the diagnostic output. The default action for
each consistency correction is to wait for the operator to respond yes or no. If the operator does not have
write permission, fsck defaults to a -n action.
Options
fsck recognizes the following options:
-F hfs Specify the HFS file system.
-c size Set the size of the buffer cache which fsck uses to cache disk blocks. size is the number
of cache blocks, and is between 0 and 100 inclusive. The most common use of this option
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1