Re: Question about tape backup of online database.

"Robert B. Easter" wrote:
>
> I'd like to know what hardware and software people use to perform tape backup
> of an online database on Linux. I would imagine the following might work(?):
>
> 1. Use RAID mirroring of the disk the db is on onto 2 two or more other
> disks.
> 2. When it is time to do the backup, disconnect one of the disks from the
> mirror and then dump the whole disk partition to a tape(s).

That won't do unless you take the database down for the disconnect - a
live database's file image may not be consistent over a backup. pg_dump
is the only supplied way to dump a live database.

> 3. Reconnect the disk back to the mirror and let it begin rebuilding.
>
> Right now, I don't even have SCSI! If you can tell me your setup and
> backup procedure, I'd be grateful.

If you do not want to take the database offline or save to a temporary
file, I'd suggest something like "mt rewind ; pg_dump -o -z >
/dev/tape". There is a new pg_dump/pg_restore out in beta now as
pg_backupXXX_latest on the PostgreSQL site which appears to be neater
than the dumper supplied in the PostgreSQL tarball.

Sevo

--
Sevo Stille
sevo(at)ip23(dot)net