Message-ID: <F001.005CA7C4.20030813075429@fatcity.com>
Date: Wed, 13 Aug 2003 07:54:29 -0800
To: Multiple recipients of list ORACLE-L <ORACLE-L@fatcity.com>
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From: Jared Still <jkstill@cybcon.com>
Subject: Re: Raid 1 vs Raid 5 for tablespaces
Organization: Fat City Network Services, San Diego, California
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Tim,

Are you suggesting that HW RAID 1 with SW RAID 0 is a better
combination than HW RAID 1 and HW RAID 0?

If so, why?

Jared

On Tue, 2003-08-12 at 21:59, Tim Gorman wrote:
> 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@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@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@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
> >> --
> >> Author: Tim Gorman
> >>   INET: tim@sagelogix.com
> >> 
> >> Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
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> 
> -- 
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> -- 
> Author: Tim Gorman
>   INET: tim@sagelogix.com
> 
> Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
> San Diego, California        -- Mailing list and web hosting services
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> To REMOVE yourself from this mailing list, send an E-Mail message
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> 


-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Jared Still
  INET: jkstill@cybcon.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
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