Re: SSD + RAID

On 11/17/2009 01:51 PM, Greg Smith wrote:
> Merlin Moncure wrote:
>> 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.
> The funny thing about Murphy is that he doesn't visit when things are
> quiet.  It's quite possible the window for data loss on the drive is
> very small.  Maybe you only see it one out of 10 pulls with a very
> aggressive database-oriented write test.  Whatever the odd conditions
> are, you can be sure you'll see them when there's a bad outage in
> actual production though.
>
> A good test program that is a bit better at introducing and detecting
> the write cache issue is described at
> http://brad.livejournal.com/2116715.html
>

I've been following this thread with great interest in your results...
Please continue to share...

For write cache issues - is it possible that the reduced power
utilization of SSD allows for a capacitor to complete all scheduled
writes, even with a large cache? Is it this particular drive you are
suggesting that is known to be insufficient or is it really the
technology or maturity of the technology?

Cheers,
mark

--
Mark Mielke<mark@mielke.cc>