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Re: Intel SSDs that may not suck

From: Jesper Krogh <jesper(at)krogh(dot)cc>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Intel SSDs that may not suck
Date: 2011-03-29 16:12:25
Message-ID: 4D9204E9.1060403@krogh.cc (view raw or flat)
Thread:
Lists: pgsql-performance
On 2011-03-29 16:16, Jeff wrote:
>  halt for 0.5-2 seconds, then resume. The fix we're going to do is
>  replace each drive in order with the rebuild occuring between each.
>  Then we do a security erase to reset the drive back to completely
>  empty (including the "spare" blocks kept around for writes).

Are you replacing the drives with new once, or just secure-erase and 
back in?
What kind of numbers are you drawing out of smartmontools in usage figures?
(Also seeing some write-stalls here, on 24 Raid50 volumes of x25m's, and
have been planning to cycle drives for quite some time, without actually
getting to it.

>  Now that all sounds awful and horrible until you get to overall
>  performance, especially with reads - you are looking at 20k random
>  reads per second with a few disks. Adding in writes does kick it
>  down a noch, but you're still looking at 10k+ iops. That is the
>  current trade off.

Thats also my experience.
-- 
Jesper

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Subject: Re: Intel SSDs that may not suck
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