Re: High Availability: Hot Standby vs. Warm Standby

Brad Nicholson wrote:
> One further thing to mention - all of these solutions are based on
> making the physical blocks available (actually, I'm not sure about
> Streaming replication in 9.0).

You're right here; the SR feature in 9.0 is essentially near real-time
partial WAL file shipping, and the WAL contains physical disk block
change data.  If your master has data blocks corrupted, the next time
you do a base backup against it that corruption will be mirrored to the
standby too.  I've mentioned on one of these lists recently that I like
to schedule a periodic pg_dump even if log shipping is the main backup
mechanism for a database, just so that corruption in the underlying
files is caught as early as possible by trying to read every block and
confirm it has valid data.

--
Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us