Managing the VxFS filesystem

Running fsck on a VxFS filesystem

This section describes the use of fsck with VxFS filesystems.

The VxFS filesystem uses a tracking feature called intent logging to record pending changes to the filesystem structure. These changes are recorded in an ``intent log''. The VxFS fsck utility typically runs an intent log replay, which scans the intent log and completes or nullifies any pending updates. With VxFS, it is seldom necessary to run a full filesystem check.

NOTE: By default, the VxFS-specific fsck only runs an intent log replay, and does not perform a full filesystem check. The full filesystem check is provided, however, to handle cases where a filesystem is damaged due to I/O failure.

The following is the VxFS-specific format of the fsck command:

fsck [-F vxfs] -m special
fsck [-F vxfs] -n|N special
fsck [-F vxfs] [-o nolog,full] [-y|Y] special

The options are as follows:

-m: Check for mountability. To determine if a filesystem can be mounted, the -m option is specified.
-n: This option runs a full filesystem check. Specifying the -n option generates a report on errors but does not make any repairs in conjunction with those errors. Intent log replay is not performed. This form of the command can be run safely on mounted filesystems on which there might have been damage. If filesystem damage is suspected, a full fsck should be run to determine the extent of filesystem damage. (A full filesystem check is specified with the -o full option.)
-N: Synonym for -n
-y: Answer yes to all questions. This option has two ramifications. First, after an intent log replay is run, if the filesystem is not in a mountable state, a full filesystem check is initiated automatically. Second, yes is automatically answered to all questions posed by the full filesystem check.
-Y: Synonym for -y.
-o nolog: Inhibit log replay. An intent log replay is not performed. This option can be used to disable log replay, if the intent log is physically damaged.
-o full: Force full filesystem check. By default, only a log replay is run.

A full filesystem check is normally interactive, meaning the system administrator is prompted before any corrective actions are taken. This is not true if the -y or -n options are used. When these options are used, fsck automatically answers yes or no to prompts, instead of waiting for input.