Continuous On-line Backups

Okay, the picture is becoming clearer (to me) in terms of a
continuous on-line backup scenario with postgres, and now I'd like to
get more understanding of how flexible it is.

Currently, I nightly pg_dump an entire cluster. I ship it to a remote
server where I restore it. This has dual utility as a verification of
the quality of the dump as well as creating a standby database
cluster that could be used in a pinch during a failover. I also ship
the dump to an off-site location as an extra safeguard.

Continuous on-line backups are promoted as a high availability option
because they would allow the failover process to occur such that the
standby is much less behind than the standby in my current scenario.
But it seems like I'll be losing a little flexibility in terms of
redundancy and verification. The way I understand it, continuous on-
line backups are actually in recovery mode until a failover scenario
occurs. I.e., restore_command actually prevents recovery.done from
being created by perpetually waiting on more WAL segment files. This
renders the recovery database useless until an event is triggered.

Is this a correct assessment?

So long as I know that nothing will access the recovery database with
write activity, is there a way to toggle the continuity so that I
could allow recovery to complete on a nightly basis, pg_dump the
recovered database (a read-only action), and then resume recovering?

--
Thomas F. O'Connell
Database Architecture and Programming
Co-Founder
Sitening, LLC

http://www.sitening.com/
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