From: Arjen van der Meijden <acmmailing@tweakers.net>
To: James Mansion <james@mansionfamily.plus.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: SSDs
Date: Wed, 02 Apr 2008 08:44:39 +0200
Message-ID: <47F32B57.9020701@tweakers.net> (raw)
In-Reply-To: <47F324B4.6010404@mansionfamily.plus.com>
References: <47F324B4.6010404@mansionfamily.plus.com>
My colleague has tested a single Mtron Mobo's and a set of 4. He also
mentioned the write performance was pretty bad compared to a Western
Digital Raptor. He had a solution for that however, just plug the SSD in
a raid-controller with decent cache performance (his favorites are the
Areca controllers) and the "bad" write performance is masked by the
controller's cache. It wood probably be really nice if you'd get tuned
controllers for ssd's so they use less cache for reads and more for writes.
Best regards,
Arjen
On 2-4-2008 8:16, James Mansion wrote:
> Tried harder to find info on the write cycles: found som CFs that claim
> 2million
> cycles, and found the Mtron SSDs which claim to have very advanced wear
> levelling and a suitably long lifetime as a result even with an
> assumption that
> the underlying flash can do 100k writes only.
>
> The 'consumer' MTrons are not shabby on the face of it and not too
> expensive,
> and the pro models even faster.
>
> But ... the spec pdf shows really hight performance for average access,
> stream
> read *and* write, random read ... and absolutely pants performance for
> random
> write. Like 130/s, for .5k and 4k writes.
>
> Its so pants it looks like a misprint and it doesn't seem to square with
> the
> review on tomshardware:
> http://www.tomshardware.com/2007/11/21/mtron_ssd_32_gb/page7.html
>
> Even there, the database IO rate does seem lower than you might hope,
> and this *might* be because the random reads are very very fast and the
> random writes ... aren't. Which is a shame, because that's exactly the
> bit I'd hope was fast.
>
> So, more work to do somewhere.
>
>
>
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To: pgsql-performance@postgresql.org
Cc: acmmailing@tweakers.net, james@mansionfamily.plus.com
Subject: Re: SSDs
In-Reply-To: <47F32B57.9020701@tweakers.net>
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