On Tue, 16 Jun 2009, Just Someone wrote:

In case the volume got corrupted (a very rare situation, as the EBS
volumes are very durable), there are snapshots I can recover from and
the WAL files I stream to another storage system (Amazon's S3).

I wouldn't go so far as to say "very durable", because the failure rate they aim for isn't really very high relative to what people expect when you use that term in a database context. The most definitive commentary I've found on this is at http://solutions.amazonwebservices.com/connect/thread.jspa;jsessionid=96A862FA1DC393FCDD94DAF0B43CF4E7?messageID=111953 where they say "we aim to provide an annual failure rate (AFR) of 0.1% - 0.5% for volumes"; frankly, that's garbage to most database people. But, as you say, when combined with an alternative backup strategy when that happens, the easy provisioning and such can give a reasonable system design for some goals. You just have to recognize that the volumes are statistically pretty fragile compared to a traditional RAID configuration on dedicated hardware and plan accordingly.

--
* Greg Smith gsm...@gregsmith.com http://www.gregsmith.com Baltimore, MD

--
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general

Reply via email to