[linux-lvm] performance probs: snapshots on mp-systems
Heinz J . Mauelshagen
mauelshagen at sistina.com
Wed Dec 19 10:15:02 UTC 2001
On Mon, Dec 17, 2001 at 05:51:52PM +0100, Martin Petermann wrote:
> Hi all,
>
> I have running SuSE 7.2 (2.4.4 kernel) on a dual processor machine (2x833
> Mhz Pentium III). I made a snapshot of the following configuration:
>
> >lvcreate -L 100M -n snapshot -c 4 -s /dev/vgfortest/testfs1
> lvcreate -- WARNING: the snapshot will be automatically disabled once it
> gets full
> lvcreate -- doing automatic backup of "vgfortest"
> lvcreate -- logical volume "/dev/vgfortest/snapshot" successfully created
>
> peanuts:root /
> >lvscan
> lvscan -- ACTIVE "/dev/mediastore/data" [100 GB]
> lvscan -- ACTIVE "/dev/vgfortest/bigfs" [8 GB]
> lvscan -- ACTIVE Original "/dev/vgfortest/testfs1" [500 MB]
> lvscan -- ACTIVE "/dev/vgfortest/testfs3" [500 MB]
> lvscan -- ACTIVE "/dev/vgfortest/smallfs" [60 MB]
> lvscan -- ACTIVE Snapshot "/dev/vgfortest/snapshot" [98.54 MB] of
> /dev/vgfortest/testfs1
> lvscan -- ACTIVE "/dev/zweite_testvg/testfs1" [500 MB]
> lvscan -- ACTIVE "/dev/zweite_testvg/testfs3" [500 MB]
> lvscan -- ACTIVE "/dev/zweite_testvg/testfs" [200 MB]
> lvscan -- 9 logical volumes with 110.3 GB total in 3 volume groups
> lvscan -- 9 active logical volumes
>
> The vg vgfortest is on a fc disk.
>
> This first run I did in multi processor mode:
>
> >time cat /dev/vgfortest/snapshot > /BIGFS/file
> 1136.72s real 0.13s user 15.87s system
>
> in single processor mode:
>
> peanuts[root]/> time cat /dev/vgfortest/snapshot > /BIGFS/file
> 402.03s real 0.10s user 16.16s system
>
> Is this problem known? Does there exist a fix?
Martin,
have heard about it for the first time.
Have you tried a newer kernel with the recent VM enhancements?
>
> Thanks for any help!
>
> Martin
>
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm at sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
--
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 at Sistina.com +49 2626 141200
FAX 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
More information about the linux-lvm
mailing list