DUMP: Warning - block NNN is beyond the end of DEVICE
This article is a part of the Troubleshooting collection.
Problem
Dump gives an error like
DUMP: Warning - block 223391968 is beyond the end of `/dev/rdsk/c2t2d0s3'
and sometimes
DUMP: bread: dev_seek error: Error 0
Explanation
This can be the result of a corrupt filesystem, but more often it is a result of dump having trouble handling an active filesystem: the filesystem has changed while it was working, and as a result it read invalid data.
See http://www.mail-archive.com/[email protected]/msg27659.html.
Solution
If it happens only now and then, don't worry. Try to not run any programs that do heavy input/output during the backup, if possible.
If it happens frequently, use snapshots, if your OS permits it, to freeze a filesystem in a few seconds, and make a backup of that snapshot.
Or use gnutar instead of ufsdump, which, at least, manages to make a consistent backup of everything that did not change -- files that did change may be inconsistent, and gnutar warns which ones (logfiles that are only appended, are nevertheless consistent).
(Thanks to Paul Bijnens)