| From: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
|---|---|
| To: | "Jeffrey W(dot) Baker" <jwbaker(at)acm(dot)org> |
| Cc: | Peter Darley <pdarley(at)kinesis-cem(dot)com>, Pgsql-Performance <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Battery Backed Cache for RAID |
| Date: | 2005-09-14 20:03:24 |
| Message-ID: | 20050914200324.GB26714@surnet.cl |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
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?
--
Alvaro Herrera -- Valdivia, Chile Architect, www.EnterpriseDB.com
Hi! I'm a .signature virus!
cp me into your .signature file to help me spread!
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Merlin Moncure | 2005-09-14 20:17:06 | Re: Battery Backed Cache for RAID |
| Previous Message | Jeffrey W. Baker | 2005-09-14 18:28:43 | Re: Battery Backed Cache for RAID |