From: Ming Zhang <mingz@ele.uri.edu>
To: Guy <bugzilla@watkins-home.com>
Cc: linux-raid@vger.kernel.org
Subject: RE: md on partition
Date: Sat, 23 Oct 2004 11:52:29 -0400 [thread overview]
Message-ID: <1098546749.3117.50.camel@localhost.localdomain> (raw)
In-Reply-To: <200410230607.i9N677N10676@www.watkins-home.com>
thx but i met this problem.
i use 4 x 400GB SATA disks, i make a raid 0 or 5, and build a vg on top
of md, then use bonnie++ to test read performance.
LVM (MD = sda+sdb+..) = 95MBsec, md is built on top of whole disk.
LVM (MD = sda1+sdb1+.) = 48MBsec, md is built on top of each partition.
so where is the problem? does md chunk size matter? or lvm extent size
matters? thx.
ming
On Sat, 2004-10-23 at 02:07, Guy wrote:
> I found this old message:
> "On Tuesday June 1, maheshext3@yahoo.com wrote:
> >
> > --- Neil Brown <neilb@cse.unsw.edu.au> wrote:
> > >
> > > What does
> > > ls -l /dev/hd[eg]5
> > > show? How about
> > > cat /proc/partitions
> > > dd if=/dev/hde5 of=/dev/null bs=1024k
> >
> > Thanks a lot, Neil, turns out those nodes were not present. After I
> > mknod'd them, all's fine in RAIDland...
> > Quick question: does using extended partitions for RAID affect
> > performance?
>
> The fact that the partitions are "extended" is invisible to most of the
> kernel, and it could not have any affect of performance.
>
> NeilBrown"
>
> Guy
>
> -----Original Message-----
> From: linux-raid-owner@vger.kernel.org
> [mailto:linux-raid-owner@vger.kernel.org] On Behalf Of Ming Zhang
> Sent: Friday, October 22, 2004 1:28 PM
> To: linux-raid@vger.kernel.org
> Subject: md on partition
>
> Hi folks.
>
> I remembered that there was a discussion on the list about some abnormal
> performance penalty if u use a partition instead of a whole disk for MD.
> But I could not find this discussion via archival or google.
>
> Could somebody be kindly enough to point me to the right spot? Thanks a
> lot.
>
> Ming
>
>
> -
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> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
--------------------------------------------------
| Ming Zhang, PhD. Student
| Dept. of Electrical & Computer Engineering
| College of Engineering
| University of Rhode Island
| Kingston RI. 02881
| e-mail: mingz at ele.uri.edu
| Tel. (401) 874-2293
| Fax. (401) 782-6422
| http://www.ele.uri.edu/~mingz/
| http://crab.ele.uri.edu/gallery/albums.php
--------------------------------------------------
next prev parent reply other threads:[~2004-10-23 15:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-22 17:27 md on partition Ming Zhang
2004-10-23 6:07 ` Guy
2004-10-23 15:52 ` Ming Zhang [this message]
2004-10-23 16:12 ` Guy
2004-10-23 22:38 ` Ming Zhang
2004-10-23 22:52 ` Guy
2004-10-23 23:04 ` Ming Zhang
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