Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id 39B9BB5DD11 for ; Fri, 2 Sep 2011 11:30:15 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 21279-02 for ; Fri, 2 Sep 2011 14:30:08 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from smtp.peak6.com (smtp.peak6.com [38.98.137.6]) by mail.postgresql.org (Postfix) with ESMTP id 80091B5DD07 for ; Fri, 2 Sep 2011 11:30:08 -0300 (ADT) X-AuditID: 0a64cb1e-b7c2bae0000029bf-71-4e60e86a708a Message-ID: <4E60E86F.2070901@peak6.com> Date: Fri, 2 Sep 2011 09:30:07 -0500 From: Shaun Thomas Reply-To: Organization: Peak6 User-Agent: Mozilla/5.0 (X11; Linux i686; rv:5.0) Gecko/20110624 Thunderbird/5.0 MIME-Version: 1.0 To: Jesper Krogh CC: Subject: Re: Summaries on SSD usage? References: <4E60583A.4040302@krogh.cc> In-Reply-To: <4E60583A.4040302@krogh.cc> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed content-transfer-encoding: 7bit X-Originating-IP: [10.10.220.61] X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrMIsWRmVeSWpSXmKPExsXCxcQrppv9IsHPYMc3NoueX+sZLa7PPMfs wOTxe2YXi8eFfdPYA5iiGhhtEvPy8ksSS1IVUlKLk22VAlwdvc0UgksS81ISi1IUXDKLk3MS M3NTi5QUMlNslYyUFApyEpNTc1PzSmyVEgsKUvNSlOy4FDCADVBZZp5Cal5yfkpmXrqtkmew v66FhamlrqGSXTwCJLSxZHQsOclS8I6t4ubhBsYGxh2sXYwcHBICJhILngp0MXICmWISF+6t ZwMJ8wpoSDzfLA0SZhFQkTizayoziM0moCaxcPdNRhBbSEBWYv+qc6wgNr+AsMS+D01gNaIC ARILJr0Fq+EVEJQ4OfMJC4gtIqAksXfVXDCbGWjO3IeTwHqFBfQkTv06BWRzAc2cyyjx5/QK NpAEJ9ANZ9+9YINosJW4MOc6VLO8xPa3c5ghjpCTuNPwnA3iFQWJ68v9JzAKzUKyehaS7llI uhcwMq9iFC8uS0zOyDQtKM4tKTDUK0hNzDbTy0st2cQIitqU03I7GKcvVTzEKMDBqMTDK7Ir 3k+INbGsuDL3EKMEB7OSCO+viQl+QrwpiZVVqUX58UWlOanFhxi1gWE2kVmKOzkfmFDySuKN DQyUxHl9ZnP4CQmkA5NAdmpqQWoRTDUTB6dUAyNrxKOLFzsuW327z8P/lqFv+mVm21ddKjGv g18Jp9qb/8uTzeS9KK55L7UxMODL9/ojq7/n6cRlZ3saCsrp7an38dLlL6k6K1Xw2S82cJrz 48jFqed3LpLU52gLTNwZb7JQa5++h+KMpHuSJ3OuGew6xxZUkquf8uap3J9fC08Krn0nlhf5 UYmlOCPRUIu5qDgRADzGAcfmAgAA X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.404 tagged_above=-10 required=5 tests=BAYES_00=-1.9, RP_MATCHES_RCVD=-0.504 X-Spam-Level: X-Archive-Number: 201109/11 X-Sequence-Number: 44787 On 09/01/2011 11:14 PM, Jesper Krogh wrote: > It is "really expensive" to go over 512GB memory and the performance > regression for just hitting disk in a system where you assume > everything is in memory is really huge. SSD makes the "edge" be a bit > smoother than rotating drives do. Ironically, this is actually the topic of my presentation at Postgres Open. We transitioned to NVRAM PCI cards for exactly this reason. Having a giant database in cache is great, until a few reads come from your slow backing disks, or heaven-forbid, you have to restart your database during a high transactional period. Lemme tell ya... no RAID-10 in the world can supply 12k TPS with little to no warning. A good set of SSDs or PCI cards can. -- Shaun Thomas OptionsHouse | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604 312-676-8870 sthomas@peak6.com ______________________________________________ See http://www.peak6.com/email_disclaimer.php for terms and conditions related to this email