Lustre 1.6 Operations Manual

22.3.3 OST Object is Missing or Damaged
If the OSS fails to find an object or finds a damaged object, this message appears:
OST object missing or damaged (OST "ost1", object 98148, error -2)
If the reported error is -2 (-ENOENT, or "No such file or directory"), then the object
is missing. This can occur either because the MDS and OST are out of sync, or
because an OST object was corrupted and deleted.
If you have recovered the filesystem from a disk failure by using e2fsck, then
unrecoverable objects may have been deleted or moved to /lost+found on the raw
OST partition. Because files on the MDS still reference these objects, attempts to
access them produce this error.
If you have recovered a backup of the raw MDS or OST partition, then the restored
partition is very likely to be out of sync with the rest of your cluster. No matter
which server partition you restored from backup, files on the MDS may reference
objects which no longer exist (or did not exist when the backup was taken);
accessing those files produces this error.
If neither of those descriptions is applicable to your situation, then it is possible that
you have discovered a programming error that allowed the servers to get out of
sync. Please report this condition to the Lustre group, and we will investigate.
If the reported error is anything else (such as -5, "I/O error"), it likely indicates a
storage failure. The low-level filesystem returns this error if it is unable to read from
the storage device.
Suggested Action
If the reported error is -2, you can consider checking in /lost+found on your raw
OST device, to see if the missing object is there. However, it is likely that this object
is lost forever, and that the file that references the object is now partially or
completely lost. Restore this file from backup, or salvage what you can and delete it.
If the reported error is anything else, then you should immediately inspect this
server for storage problems.
Chapter 22 Lustre Troubleshooting Tips 22-5