X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 9EB23D8F08 for ; Wed, 14 Sep 2005 17:47:35 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 43395-01 for ; Wed, 14 Sep 2005 20:47:29 +0000 (GMT) Received: from olive.qinip.net (olive.qinip.net [62.100.30.40]) by svr1.postgresql.org (Postfix) with ESMTP id D174CD8EF2 for ; Wed, 14 Sep 2005 17:47:29 -0300 (ADT) Received: from [10.0.0.2] (h8441139206.dsl.speedlinq.nl [84.41.139.206]) by olive.qinip.net (Postfix) with ESMTP id 9565E181D6; Wed, 14 Sep 2005 22:47:26 +0200 (MEST) Message-ID: <43288C67.3000209@tweakers.net> Date: Wed, 14 Sep 2005 22:47:35 +0200 From: Arjen van der Meijden User-Agent: Mozilla Thunderbird 1.0RC1 (Windows/20041201) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Alvaro Herrera Cc: "Jeffrey W. Baker" , Peter Darley , Pgsql-Performance Subject: Re: Battery Backed Cache for RAID References: <1126722523.27650.6.camel@toonses.gghcwest.com> <20050914200324.GB26714@surnet.cl> In-Reply-To: <20050914200324.GB26714@surnet.cl> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0 required=5 tests=[none] X-Spam-Level: X-Archive-Number: 200509/196 X-Sequence-Number: 14504 On 14-9-2005 22:03, Alvaro Herrera wrote: > On Wed, Sep 14, 2005 at 11:28:43AM -0700, Jeffrey W. Baker wrote: > >>On Wed, 2005-09-14 at 11:25 -0700, Peter Darley wrote: >> >>Actually the cache will just hold its contents while the power is out. >>When the power is restored, the RAID controller will complete the writes >>to disk. If the battery does not last through the outage, the data is >>lost. > > > Just curious: how long are the batteries supposed to last? For the LSI-Logic MegaRaid 320-2e its about 72 hours for the standard 128MB version. Their SATA2-solution offers 32 and 72 hour-options. So I assume its "in the order of days" for most RAID controllers. Best regards, Arjen van der Meijden