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[linux-lvm] performance writing to an lv with no file system



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 ***

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Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
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                                                  Germany
Mauelshagen Sistina com                           +49 2626 141200
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