Repairing a Corrupted File or Directory

If a file or directory is corrupted, the system might still be able to function depending on the type of corruption. Any damage is effectively unrecoverable if no good copies of the data exist anywhere on the system. If the data is valuable, you have no choice but to restore the affected data from backup. Even so, you might be able to recover from this corruption without restoring the entire pool.

If the damage is within a file data block, then the file can safely be removed, thereby clearing the error from the system. Use the zpool status -v command to display a list of filenames with persistent errors. For example:

# zpool status -v
   pool: monkey
state: ONLINE
status: One or more devices has experienced an error resulting in data
         corruption.  Applications may be affected.
action: Restore the file in question if possible.  Otherwise restore the
         entire pool from backup.
    see: http://www.sun.com/msg/ZFS-8000-8A
scrub: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         monkey      ONLINE       0     0     0
           c1t1d0s6  ONLINE       0     0     0
           c1t1d0s7  ONLINE       0     0     0

errors: Permanent errors have been detected in the following files: 

/monkey/a.txt
/monkey/bananas/b.txt
/monkey/sub/dir/d.txt
monkey/ghost/e.txt
/monkey/ghost/boo/f.txt

A list of filenames with persistent errors might be described as follows:

• If the full path to the file is found and the dataset is mounted, the full path to the file is displayed. For example:

  /monkey/a.txt

• If the full path to the file is found, but the dataset is not mounted, then the dataset name with no preceding slash (/), followed by the path within the dataset to the file, is displayed. For example:

  monkey/ghost/e.txt

• If the object number to a file path cannot be successfully translated, either due to an error or because the object doesn't have a real file path associated with it, as is the case for a dnode_t, then the dataset name followed by the object's number is displayed. For example:

  monkey/dnode:<0x0>

• If an object in the meta-object set (MOS) is corrupted, then a special tag of <metadata>, followed by the object number, is displayed.

If the corruption is within a directory or a file's metadata, the only choice is to move the file elsewhere. You can safely move any file or directory to a less convenient location, allowing the original object to be restored in place.