Re: Raid 1 vs Raid 5 for tablespaces

From: Tim Gorman <tim_at_sagelogix.com>
Date: Tue, 12 Aug 2003 20:59:24 -0800
Message-ID: <F001.005CA59C.20030812205924@fatcity.com>

Software RAID-1 can mirror across controllers, channels, and storage arrays, should any of those be considered a single-point-of-failure...

The combination of HW RAID-1 and SW RAID-0 is optimal for performance, if the HW supports it...

on 8/12/03 9:04 PM, Matthew Zito at mzito_at_gridapp.com wrote:

> 
> Actually, as of AIX 4.3.3, it does support 0+1 for LVs, but that wasn't the
> scenario I was imagining.  I was envisioning creating a set of RAID-1 raid
> groups on the storage array and then striping across them using the LVM.
> RAID-1 is one of those things that I feel is generally better to let your
> storage array handle - software RAID-1 requires your host to generate double
> the I/Os and should one side of the pair fail, hardware arrays tend to
> recover more gracefully than software raid.  RAID-0, by comparison, is very
> easy.
> 
> Thanks,
> Matt
> 
> 
> ----- Original Message -----
> To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
> Sent: Tuesday, August 12, 2003 9:44 PM
> 
> 

>> The AIX LVM supports RAID-0 and RAID-1, but not together, as you state.
>>
>> However, a rude form of RAID-0 can be achieved by specifying "max

> allocation

>> policy", which will cause round-robin distribution of physical extents

> (PEs)

>> across a list of physical volumes (PVs), thereby approximately RAID-0 at a
>> large granularity (i.e. 4M, 8M, 16M per "stripe"). Still, it beats the

> heck

>> out of RAID5...
>>
>>
>> on 8/12/03 12:24 PM, Schauss, Peter at peter.schauss_at_ngc.com wrote:
>>

>>> Our hardware people tell me that our disk array will not support Raid
> 10.
>>> Given a choice between Raid 1 or 5 for my tablespaces, which one
>>> is best?  This is Oracle 8.1.7 on AIX 4.3.3.  The application will
>>> have a mix of read and write activity.
>>> 
>>> Thanks,
>>> Peter Schauss

>>
>> --
>> Please see the official ORACLE-L FAQ: http://www.orafaq.net
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>> Author: Tim Gorman
>> INET: tim_at_sagelogix.com
>>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Tim Gorman
  INET: tim_at_sagelogix.com

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Received on Tue Aug 12 2003 - 23:59:24 CDT