On Jun 21, 2007, at 7:30 PM, Toru SHIMOGAKI wrote:
Tom Lane wrote:
Dan Gorman <dgorman@xxxxxxx> writes:
All of our databases are on NetApp storage and I have been
looking
at SnapMirror (PITR RO copy ) and FlexClone (near instant RW volume
replica) for backing up our databases. The problem is because there
is no write-suspend or even a 'hot backup mode' for postgres it's
very plausible that the database has data in RAM that hasn't been
written and will corrupt the data.
Alternatively, you can use a PITR base backup as suggested here:
http://www.postgresql.org/docs/8.2/static/continuous-archiving.html
I think Dan's problem is important if we use PostgreSQL to a large
size database:
- When we take a PITR base backup with hardware level snapshot
operation
(not filesystem level) which a lot of storage vender provide, the
backup data
can be corrupted as Dan said. During recovery we can't even read it,
especially if meta-data was corrupted.
I can't see any explanation for how this could happen, other
than your hardware vendor is lying about snapshot ability.
What problems have you actually seen?
Cheers,
Steve
