Re: SSD + RAID

On Tue, 2009-11-17 at 11:36 -0500, Merlin Moncure wrote:
> 2009/11/13 Greg Smith <greg(at)2ndquadrant(dot)com>:
> > As far as what real-world apps have that profile, I like SSDs for small to
> > medium web applications that have to be responsive, where the user shows up
> > and wants their randomly distributed and uncached data with minimal latency.
> > SSDs can also be used effectively as second-tier targeted storage for things
> > that have a performance-critical but small and random bit as part of a
> > larger design that doesn't have those characteristics; putting indexes on
> > SSD can work out well for example (and there the write durability stuff
> > isn't quite as critical, as you can always drop an index and rebuild if it
> > gets corrupted).
>
> I am right now talking to someone on postgresql irc who is measuring
> 15k iops from x25-e and no data loss following power plug test. I am
> becoming increasingly suspicious that peter's results are not
> representative: given that 90% of bonnie++ seeks are read only, the
> math doesn't add up, and they contradict broadly published tests on
> the internet. Has anybody independently verified the results?

How many times have the run the plug test? I've read other reports of
people (not on Postgres) losing data on this drive with the write cache
on.

--
Brad Nicholson 416-673-4106
Database Administrator, Afilias Canada Corp.