Re: asm on san
From: Michael Austin <maustin_at_firstdbasource.com>
Date: Sun, 14 Dec 2008 13:25:58 -0600
Message-ID: <25d1l.9923$yr3.5770@nlpi068.nbdc.sbc.com>
>
> I have had problems with "waiting for free buffers" when one of the
> data files was located on a RAID 5 LUN (EMC CX 700, rather high end
> SAN). When the file was copied to a RAID 1+0 LUN, the problems with
> DB writer went away. That was a fairly high end OLTP database.
> Unfortunately, not all SAN devices have that many gigabytes of memory.
> I still subscribe to the BAARF doctrine: RAID 5 is not for databases.
>
>
>
Date: Sun, 14 Dec 2008 13:25:58 -0600
Message-ID: <25d1l.9923$yr3.5770@nlpi068.nbdc.sbc.com>
Mladen Gogala wrote:
> On Sat, 13 Dec 2008 11:21:35 -0600, Michael Austin wrote:
>
>> And when it comes to >> performance, as I stated, there are but a handful of systems that RAID10 >> vs RAID5 would ever make any real difference in performance. If I >> needed to build one of those systems, you could bet it would be a >> completely dedicated environment.
>
> I have had problems with "waiting for free buffers" when one of the
> data files was located on a RAID 5 LUN (EMC CX 700, rather high end
> SAN). When the file was copied to a RAID 1+0 LUN, the problems with
> DB writer went away. That was a fairly high end OLTP database.
> Unfortunately, not all SAN devices have that many gigabytes of memory.
> I still subscribe to the BAARF doctrine: RAID 5 is not for databases.
>
>
>
I wouldn't go that far... :) I my experience, I would have to say that as far as Oracle and SAN go, I am not fan of EMC - especially the CX models. I have always had issues with their internal structures (software and hardware). When I put them up against a couple of other vendors - with similar RAID settings, I do not see these sort of issues. Received on Sun Dec 14 2008 - 13:25:58 CST