Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!sgi!daveh@xtenk.asd.sgi.com
From: daveh@xtenk.asd.sgi.com (David Higgen)
Newsgroups: comp.sys.sgi
Subject: Re: logical volumes & striping
Message-ID: <103528@sgi.sgi.com>
Date: 13 May 91 20:21:12 GMT
References: <9105101949.AA20619@centrs1.CENTRCN.UMontreal.CA>
Sender: guest@sgi.sgi.com
Organization: Silicon Graphics, Inc., Mountain View, CA
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In article <9105101949.AA20619@centrs1.CENTRCN.UMontreal.CA>, chouinar@centrcn.umontreal.ca (Luc Chouinard) writes:
> We have 6 scsi disks on two controlers, and we are
> considering using a striped logical volume for one
> of our partitions.
> 
> We currently believe that striping is always a good thing
> to do.  
> 
> We have just been advised by a knowledgeable person that
> this would not be true in all cases, specifically ours.
> And the explanation that was given to us makes sense.

Would you care to mail me this explanation? I would like to see
if it makes sense to me & may be able to advise you better: I am the
author of SGI's logical volume implementation.

> More specifically, we would like to know if there is an
> overhead associated with accessing a single block in a
> striped logical volume, versus a standard partition.

The overhead is negligible: a sufficiently small fraction of
a percent that we have not been able to detect it in practical
performance measurements.


		Dave Higgen (daveh@xtenk.asd.sgi.com)