Re: A few questions to real pgsql gurus

Dennis Gearon <gearond(at)cvc(dot)net> writes:
> And what about all the stuff in memory, pending transactions, etc?

If he's got an accurate snapshot of the WAL files, everything the
database has claimed to be committed will be committed. It's the same
scenario as a crash.

The trouble with most "I'll just take a tar dump/rsync copy/whatever
of the $PGDATA directory" backup solutions is that you don't get a copy
of the WAL files that's consistent with what you copy out of the other
subdirectories --- and any time skew there will burn you. See recent
reports of duplicate rows for an example. But if NetApp can implement
an instantaneous copy (and offhand it seems that they should be able to,
since they sit between PG and the disk) then it should work.

I'd still recommend some tests before trusting it ;-)

regards, tom lane