From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3F00F024.8050006@cablespeed.com> From: Howard Clifford MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [linux-lvm] performance writing to an lv with no file system Sender: linux-lvm-admin@sistina.com Errors-To: linux-lvm-admin@sistina.com Reply-To: linux-lvm@sistina.com List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: Date: Mon Jun 30 21:22:01 2003 List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linux-lvm@sistina.com Heinz, Thank you for the response. My logical volume is striped - 7 ways. I am writing to the lv with a simple c program I wrote. Each write is 7*stripesize, which in this case is 28 blocks. Any thoughts on how I can get top speeds without mounting and unmounting the volume? Thanks, Howie > Howard, > what's the LV layout (linear/striped ?). > How do you write to the LV (dd or soemthing). > What's the write pattern (sequential ? block size ?) > 80MB/sec raw sounds like you use a striped LV. On Sun, Jun 29, 2003 at 12:08:34PM -0400, Howard Clifford wrote: > I built a 7 disk vg and put 1 lv on it. I do not want to mount a file > system. > I just want to write directly to the disk device, /dev/vg1/vol1. > > My write performance has an odd behavior. > If after booting I write to the volume I get roughly 175MB/sec. > If after booting I do a mke2fs on the volume, mount it, umount it, then > write to the volume I get roughly 230 MB/sec. > > Any ideas? How can I get top speed without first mounting then > umounting the volume? > By the way, I tried binding a raw device to the lv and got very bad > performance; around 80 MB/sec. Would that be expected? > > (I'm using redhat 9.0 -> lvm-1.0.3-12) > > Thanks... > > > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ -- Regards, Heinz -- The LVM Guy -- *** Software bugs are stupid. Nevertheless it needs not so stupid people to solve them *** =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Heinz Mauelshagen Sistina Software Inc. Senior Consultant/Developer Am Sonnenhang 11 56242 Marienrachdorf Germany Mauelshagen@Sistina.com +49 2626 141200 FAX 924446 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-