Re: Continuous On-line Backups

On Mar 24, 2006, at 5:19 PM, Peter Eisentraut wrote:

> Thomas F. O'Connell wrote:
>> 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?
>
> Even a read-only action uses up transaction numbers and other
> things, so
> I'd expect that to be a problem.

Good point.

My chief concern with the loss of flexibility would be the greater
difficulty in detecting a lost or corrupted WAL segment file if
archive_command is operating across a network (or locally, with an
external script responsible for moving the files across the network).

With nightly pg_dumps/pg_restores, at least I know my window of a
valid database is on the order of 24 hours.

Simon Riggs recently recommended base backups as a weekly process
with a continuous on-line backup operating in the interim. I guess
the price to be paid for the higher availability is increased
scrutiny of the process.

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

http://www.sitening.com/
3004 B Poston Avenue
Nashville, TN 37203-1314
615-260-0005 (cell)
615-469-5150 (office)
615-469-5151 (fax)