pkb@omsvax.UUCP (07/20/83)
Sometime back I saw somebody ask about doing backups with the system running multi-user. I never saw any responses. Were there none or did I miss them. Will someone mail me his experiences about dumps/restores (4.1bsd) of file-systems done with machine running multi-user. Thanks. Praveen Bhatia Intel ...teklabs!ogcvax!omsvax!pkb
rsm%brl-bmd@sri-unix.UUCP (07/25/83)
From: Robert S. Miles <rsm@brl-bmd> Kirk McKusick's response to this question during the 4.2 BSD File Systems Tutorial at the Toronto USENIX Conference last week: "If you want consistent dumps -- dump single user." Because DUMP uses the raw disk and goes tracing along indirect block pointers it can get confused if the file it is dumping changes while the dump is in progress. If a block which DUMP believes to be an indirect block no longer has valid indirect addressing data in it then the results are unpredictable. This is true of all the file system utilities -- their results are not to be trusted when they are run on active file systems! Therefore the safest way to do dumps is with the system down (or at very least with the file system unmounted.) -Bob Miles, rsm@BRL