Re: Battery Backed Cache for RAID

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:
> >     I'm getting a new server for our database, and I have a quick question
> > about RAID controllers with a battery backed cache.  I understand that the
> > cache will allow the cache to be written out if the power fails to the box,
> > which allows it to report a write as committed safely when it's not actually
> > committed.
>
> 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?

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Alvaro Herrera -- Valdivia, Chile         Architect, www.EnterpriseDB.com
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