[linux-lvm] performance writing to an lv with no file system
howardclifford at cablespeed.com
Mon Jun 30 21:22:01 UTC 2003
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
> 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
> 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)
> linux-lvm mailing list
> linux-lvm at sistina.com
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
Heinz -- The LVM Guy --
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