From: Arjen van der Meijden <acmmailing@tweakers.net>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Jeffrey W. Baker <jwbaker@acm.org>
Cc: Peter Darley <pdarley@kinesis-cem.com>
Cc: Pgsql-Performance <pgsql-performance@postgresql.org>
Subject: Re: Battery Backed Cache for RAID
Date: Wed, 14 Sep 2005 22:47:35 +0200
Message-ID: <43288C67.3000209@tweakers.net> (raw)
In-Reply-To: <20050914200324.GB26714@surnet.cl>
References: <PDEOIIFFBIAABMGNJAGPAELFDOAA.pdarley@kinesis-cem.com>
<1126722523.27650.6.camel@toonses.gghcwest.com>
<20050914200324.GB26714@surnet.cl>
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
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To: pgsql-performance@postgresql.org
Cc: acmmailing@tweakers.net, alvherre@alvh.no-ip.org, jwbaker@acm.org, pdarley@kinesis-cem.com
Subject: Re: Battery Backed Cache for RAID
In-Reply-To: <43288C67.3000209@tweakers.net>
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