Lustre 1.6 Operations Manual

Example:
lfsck -n -v --mdsdb /home/mdsdb --ostdb /home/ostdb \
/mnt/lustre/client/
MDSDB: /home/mdsdb
OSTDB[0]: /home/ostdb
MOUNTPOINT: /mnt/lustre/client/
MDS: max_id 288 OST: max_id 321
lfsck: ost_idx 0: pass1: check for duplicate objects
lfsck: ost_idx 0: pass1 OK (287 files total)
lfsck: ost_idx 0: pass2: check for missing inode objects
lfsck: ost_idx 0: pass2 OK (287 objects)
lfsck: ost_idx 0: pass3: check for orphan objects
[0] uuid lustre-OST0000_UUID
[0] last_id 288
[0] zero-length orphan objid 1
lfsck: ost_idx 0: pass3 OK (321 files total)
lfsck: pass4: check for duplicate object references
lfsck: pass4 OK (no duplicates)
lfsck: fixed 0 errors
By default, lfsck does not repair any inconsistencies it finds, it only reports errors.
It checks for three kinds of inconsistencies:
■ Inode exists but has missing objects = dangling inode. Normally, this happens if
there was a problem with an OST.
■ Inode is missing but the OST has unreferenced objects = orphan object. Normally,
this happens if there was a problem with the MDS.
■ Multiple inodes reference the same objects. This happens if there was corruption
on the MDS or if the MDS storage is cached and loses some, but not all, writes.
If the filesystem is busy, lfsck may report inconsistencies where none exist because
of files and objects being created/removed after the database files were collected.
Examined the results closely; you probably want to contact Lustre Support for
guidance.
The easiest problem to resolve is orphaned objects. Use the -l option to lfsck so it
links these objects to new files and puts them into lost+found in the Lustre
filesystem, where they can be examined and saved or deleted as necessary. If you are
certain that the objects are not necessary, lfsck can run with the -d option to delete
orphaned objects and free up any space they are using.
Chapter 28 User Utilities (man1) 28-17