Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id C7F7A1337BE2 for ; Wed, 6 Apr 2011 21:05:41 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 36599-07 for ; Thu, 7 Apr 2011 00:05:32 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from EXHUB018-3.exch018.msoutlookonline.net (exhub018-3.exch018.msoutlookonline.net [64.78.17.18]) by mail.postgresql.org (Postfix) with ESMTP id 1339A133655C for ; Wed, 6 Apr 2011 21:05:31 -0300 (ADT) Received: from EXVMBX018-1.exch018.msoutlookonline.net ([64.78.17.47]) by EXHUB018-3.exch018.msoutlookonline.net ([64.78.17.18]) with mapi; Wed, 6 Apr 2011 17:05:30 -0700 From: Scott Carey To: Jeff , Merlin Moncure CC: Andy , "pgsql-performance@postgresql.org" , Greg Smith Date: Wed, 6 Apr 2011 17:05:28 -0700 Subject: Re: Intel SSDs that may not suck Thread-Topic: [PERFORM] Intel SSDs that may not suck Thread-Index: Acv0t4EKBuzmE1MlT+2mdNU36cUalw== Message-ID: In-Reply-To: <8BE8F356-319F-4BE7-BE66-F45D50235985@torgo.978.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Microsoft-MacOutlook/14.2.0.101115 acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.9 tagged_above=-10 required=5 tests=BAYES_00=-1.9 X-Spam-Level: X-Archive-Number: 201104/57 X-Sequence-Number: 43119 On 3/29/11 7:16 AM, "Jeff" wrote: > >The write degradation could probably be monitored looking at svctime >from sar. We may be implementing that in the near future to detect >when this creeps up again. For the X25-M's, overcommit. Do a secure erase, then only partition and use 85% or so of the drive (~7% is already hidden). This helps a lot with the write performance over time. The Intel rep claimed that the new G3's are much better at limiting the occasional write latency, by splitting longer delays into slightly more frequent smaller delays. Some of the benchmark reviews have histograms that demonstrate this (although the authors of the review only note average latency or throughput, the deviations have clearly gone down in this generation). I'll know more for sure after some benchmarking myself. > > >-- >Jeff Trout >http://www.stuarthamm.net/ >http://www.dellsmartexitin.com/ > > > > >--=20 >Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) >To make changes to your subscription: >http://www.postgresql.org/mailpref/pgsql-performance