Message-ID: <52090030.4000503@commandprompt.com>
Date: Mon, 12 Aug 2013 08:33:04 -0700
From: "Joshua D. Drake" <jd@commandprompt.com>
Organization: Command Prompt, Inc.
User-Agent: Mozilla/5.0 (X11; Linux x86_64;
 rv:17.0) Gecko/20130803 Thunderbird/17.0.8
MIME-Version: 1.0
To: "David F. Skoll" <dfs@roaringpenguin.com>
CC: pgsql-admin@postgresql.org
Subject: Re: Opinions on SSDs
References: <20130812112833.65a97285@hydrogen.roaringpenguin.com>
In-Reply-To: <20130812112833.65a97285@hydrogen.roaringpenguin.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk
Sender: pgsql-admin-owner@postgresql.org


On 08/12/2013 08:28 AM, David F. Skoll wrote:
>
> Hi,
>
> We run a fairly write-intensive workload and are looking at upgrading
> our Pg servers.  (PostgreSQL 9.1; no practical way to upgrade to 9.2 for
> a while because we use what's packaged with Debian.)

apt.postgresql.org

>
> I'm considering the following configuration:
>
>     Dual 4-core Intel CPU (E5620 at 2.4GHz)
>
>     192GB of RAM
>
>     Sixteen 240GB Intel SSD 520 series drives arranged using Linux
>     RAID-10.  The RAID 10 array will use eight mirrored stripes using the
>     "offset-copies" RAID10 scheme.
>
> Questions:
>
> 1) Has anyone had experience with Intel 520 SSDs?  Are they reliable?
> When they fail, do they fail nicely (ie, failure detected and bad drive
> removed from RAID array) or horribly (data silently corrupted...) ?

I don't recall if the 520s have powerloss protection but you will want 
to check that.

>
> 2) Is this RAID arrangement sensible?  I've seen reports where some
> people keep the pg_xlog directory on a separate RAID array, but I
> don't really see the advantage with SSDs.

Put the pg_xlog on spindles, they are more than fast enough and won't 
eat up the write life of your SSDs.

JD


-- 
Command Prompt, Inc. - http://www.commandprompt.com/  509-416-6579
PostgreSQL Support, Training, Professional Services and Development
High Availability, Oracle Conversion, Postgres-XC, @cmdpromptinc
For my dreams of your image that blossoms
    a rose in the deeps of my heart. - W.B. Yeats


-- 
Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-admin