The volume group vg0 is the raid0 of two disk (SAS 15000rpm 300G0)
I have only this raid on the server
But i don't understand, imagine i make a volume group ou of this raid0. It is no possible to snapshot the original volume, am i wrong?
If i make a new VG on another disks, For exemple /dev/vg1/
LVM don't permit to store a snaphot on a different VG than the origin volum.
for exemple /dev/vg0/test cant be snapshoting on /dev/vg1/test.snap
LV test and LV test.snap must be on the same volume, am i wrong ???? so it is impossible to store snapshot on another disk....
| Cordialement,
|
 | |
| MARTINEAU Antony Service informatique Assistant informatique LIPPI Management | La Fouillouse 16440 Mouthiers sur Boheme Tel.: 05.45.67.34.35 Courriel: antony.martineau@lippi.fr http://www.lippi.fr |
| De : | "Larry Dickson" <ldickson@cuttedge.com> |
| Pour : | "LVM general discussion and development" <linux-lvm@redhat.com> |
| Date: | 06/06/2008 16:19 |
| Objet : | Re: Performance tunning on LVM2 |
This looks like the result of excessive seeking. Are origin volume and snapshot both on the same physical drive? Is it possible to make a volume group out of two drives, and arrange things so that origin volume and snapshot are hitting different disks?
Larry Dickson
Cutting Edge Networked Storage
On 6/6/08, Antony MARTINEAU <Antony.MARTINEAU@lippi.fr> wrote:
Hello,
My configuration:
Server DELL 2860 Intel(R) Xeon(R) CPU X3230 @ 2.66GHz (Quad Core)
8GB of memory
2 x SAS 15000 300G0 RAID 0 hardware
SLES 10 SP2
Kernel 2.6.16.60-0.21-xen
i have one volume group vg0 ( whith one PV, the two disks in raid0) whith many lvm
I am very surprise about LVM2 performance when a snapshot is done.
Write speed on the Original volume is very bad when a snaphot is active...
For exemple:
Speed on /dev/vg0/test when there is NO snapshot :
suse2:~ # dd if=/dev/zero of=/dev/vg0/test bs=2M count=400
400+0 records in
400+0 records out
838860800 bytes (839 MB) copied, 6.42741 seconds, 131 MB/s
Speed on /dev/vg0/test when there is one snapshot of this original volume :
suse2:~ # lvremove --force /dev/vg0/test3.snap
Logical volume "test3.snap" successfully removed
suse2:~ # dd if=/dev/zero of=/dev/vg0/test bs=2M count=400
400+0 records in
400+0 records out
838860800 bytes (839 MB) copied, 6.42741 seconds, 131 MB/s
suse2:~ # lvcreate -s -L1G -ntest.snap /dev/vg0/test
Logical volume "test.snap" created
suse2:~ # dd if=/dev/zero of=/dev/vg0/test bs=2M count=400
400+0 records in
400+0 records out
838860800 bytes (839 MB) copied, 204.862 seconds, 4.1 MB/s
Speed on /dev/vg0/test when there is 2 snapshots of this original volume :
suse2:~ # lvcreate -s -L1G -ntest1.snap /dev/vg0/test
Logical volume "test1.snap" created
suse2:~ # lvcreate -s -L1G -ntest2.snap /dev/vg0/test
Logical volume "test2.snap" created
suse2:~ # lvremove /dev/vg0/test2.snap
Do you really want to remove active logical volume "test2.snap"? [y/n]: y
Logical volume "test2.snap" successfully removed
suse2:~ # dd if=/dev/zero of=/dev/vg0/test bs=2M count=400
400+0 records in
400+0 records out
838860800 bytes (839 MB) copied, 270.928 seconds, 3.1 MB/s
Do you know some elements about tunning performance?,?
Performances are disastrous when a snaphot is active
Could you give your speed result? and your amelioration??
ps:Results are the same whithout Kernel Xen and whith a kernel more recent (2.6.24.2)
| Cordialement, |
 | |
| MARTINEAU Antony Service informatique Assistant informatique LIPPI Management | La Fouillouse 16440 Mouthiers sur Boheme Tel.: 05.45.67.34.35 Courriel: antony.martineau@lippi.fr http://www.lippi.fr |
Ce message et toutes les pieces jointes sont etablis a l'attention exclusive de ses destinataires et sont strictement confidentiels. Pour en savoir plus cliquer ici
This message and any attachments are confidential to the ordinary user of the e-mail address to which it was addressed and may also be privileged. More information
_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
Ce message et toutes les pieces jointes sont etablis a l'attention exclusive de ses destinataires et sont strictement confidentiels. Pour en savoir plus cliquer ici
This message and any attachments are confidential to the ordinary user of the e-mail address to which it was addressed and may also be privileged. More information
_______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
