Re: Battery Backed Cache for RAID

Bear in mind you will lose data if the raid controller itself fails (or the
cache memory module). Many solutions have mirrored cache for this reason. But
that's more $$, depending on the risks you want to take.

Quoting Arjen van der Meijden <acmmailing(at)tweakers(dot)net>:

> 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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