Re: New Disk Setup
From: onedbguru <onedbguru_at_yahoo.com>
Date: Thu, 28 May 2009 18:16:31 -0700 (PDT)
Message-ID: <746c1dd4-bf6b-46ea-83a7-df0b33b69ce2_at_e20g2000vbc.googlegroups.com>
On May 28, 8:05 pm, joel garry <joel-ga..._at_home.com> wrote:
> On May 28, 1:15 pm, Mark D Powell <Mark.Pow..._at_eds.com> wrote:
>
> > The fact that RAID-5 only protects you from the loss of a single disk
> > in the stripe is one reason I suggested two 4 disk stripes rather than
> > just a single 8 disk stripe but I have seen places use stripes with
> > over 20 disks in them. (If a single disk is likely to fail once in
> > 300 years how many disk failures would I expect if I had 300 disks?)
>
> 300 :-)
>
> (One time we managed to get a whole SAN worth of bogus disks - from
> IBM, no less. IIRC, they sold that division to Hitachi.)
>
> jg
> --
> _at_home.com is bogus.
> Bing it on:http://www3.signonsandiego.com/stories/2009/may/28/us-tec-microsoft-s...
Date: Thu, 28 May 2009 18:16:31 -0700 (PDT)
Message-ID: <746c1dd4-bf6b-46ea-83a7-df0b33b69ce2_at_e20g2000vbc.googlegroups.com>
On May 28, 8:05 pm, joel garry <joel-ga..._at_home.com> wrote:
> On May 28, 1:15 pm, Mark D Powell <Mark.Pow..._at_eds.com> wrote:
>
> > The fact that RAID-5 only protects you from the loss of a single disk
> > in the stripe is one reason I suggested two 4 disk stripes rather than
> > just a single 8 disk stripe but I have seen places use stripes with
> > over 20 disks in them. (If a single disk is likely to fail once in
> > 300 years how many disk failures would I expect if I had 300 disks?)
>
> 300 :-)
>
> (One time we managed to get a whole SAN worth of bogus disks - from
> IBM, no less. IIRC, they sold that division to Hitachi.)
>
> jg
> --
> _at_home.com is bogus.
> Bing it on:http://www3.signonsandiego.com/stories/2009/may/28/us-tec-microsoft-s...
If all 8 drives are dedicated to database files (not software) then, and the size of 4 devices is sufficient (lets be conservative and say you need 1TB of storage and you have 8 256GB drives, then I would use ASM and create 2 disk groups and put both of them in a failure group.
Disk 1-4 on controllerA
Disk 5-8 on controllerB
ASM Diskgroup AA = disk 1-4
ASM Diskgroup BB = disk 5-8
ASM FAILURE GROUP 1 = AA,BB
This will provide striping, failover and some modest performance.
Use ASM [CORRECTLY] and you won't regret it - coming from someone that has used it for a multi-hundredTB database and lets just say we added more data/day than most of these small db's in their lifetime... Received on Thu May 28 2009 - 20:16:31 CDT