Greg Smith wrote:
On Tue, 6 May 2008, Dennis Muhlestein wrote:
> Since disks are by far the most likely thing to fail, I think it would
be bad planning to switch to a design that doubles the chance of a disk
failure taking out the server just because you're adding some
server-level redundancy. Anybody who's been in this business for a
while will tell you that seemingly improbable double failures happen,
and if were you'd I want a plan that survived a) a single disk failure
on the primary and b) a single disk failure on the secondary at the same
time.
Let me strengthen that--I don't feel comfortable unless I'm able to
survive a single disk failure on the primary and complete loss of the
secondary (say by power supply failure), because a double failure that
starts that way is a lot more likely than you might think. Especially
with how awful hard drives are nowadays.
Those are good points. So you'd go ahead and add the pgpool in front
(or another redundancy approach, but then use raid1,5 or perhaps 10 on
each server?
-Dennis
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