Thanks Dave, This worked like a charm. Girish On Mon, Jun 9, 2008 at 6:10 AM, <linux-lvm-request@redhat.com> wrote: > Send linux-lvm mailing list submissions to > linux-lvm@redhat.com > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.redhat.com/mailman/listinfo/linux-lvm > or, via email, send a message with subject or body 'help' to > linux-lvm-request@redhat.com > > You can reach the person managing the list at > linux-lvm-owner@redhat.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of linux-lvm digest..." > > > Today's Topics: > > 1. striping question (Mag Gam) > 2. Loopback mount a disk image with lvm (Girish V) > 3. Re: Loopback mount a disk image with lvm (David Robinson) > 4. Re: Performance tunning on LVM2 (Heinz Mauelshagen) > 5. Re: Performance tunning on LVM2 (Antony MARTINEAU) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 7 Jun 2008 11:39:09 -0400 > From: "Mag Gam" <magawake@gmail.com> > Subject: striping question > To: linux-lvm@redhat.com > Message-ID: > <1cbd6f830806070839l436b0b4ai99d3c4264e896ea6@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > If I am using x RAID 5 volumes and create PVs. Once I create the LVs is it a > good idea to stripe them? If so, what is a valid stripe size? > > I am looking for performance BTW. > > > TIA > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: https://www.redhat.com/archives/linux-lvm/attachments/20080607/69fbc84c/attachment.html > > ------------------------------ > > Message: 2 > Date: Sun, 8 Jun 2008 18:23:23 -0400 > From: "Girish V" <girish.xen@gmail.com> > Subject: Loopback mount a disk image with lvm > To: linux-lvm@redhat.com > Message-ID: > <2122f0920806081523w7a7ce274q9707992948f6e1b4@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > Hello, > > I have a disk.img (a disk image file, raw format) with the following "fdisk -l" > > Device Boot Start End Blocks Id System > disk.img1 * 1 13 104391 83 Linux > disk.img2 14 2491 19904535 8e Linux LVM > > Now I can loopback mount the first bartition using > "mount -o loop,offset=32256 disk.img /mnt". > > I need to mount the second partition. If the secoond partition had > been an ext3 partition, I would have loopback mounted it as > "mount -o loop,offset=$((255*63*512*13) disk.img /mnt", but when I try > that, I get > mount: unknown filesystem type 'LVM2_member' > > Any help is greatly appreciated. > > Thanks. > > > > ------------------------------ > > Message: 3 > Date: Mon, 9 Jun 2008 10:52:54 +1000 > From: "David Robinson" <zxvdr.au@gmail.com> > Subject: Re: Loopback mount a disk image with lvm > To: "LVM general discussion and development" <linux-lvm@redhat.com> > Message-ID: > <b072968d0806081752s79f32e66h4c6d7de1b42094a0@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > On Mon, Jun 9, 2008 at 8:23 AM, Girish V <girish.xen@gmail.com> wrote: >> Hello, >> >> I have a disk.img (a disk image file, raw format) with the following "fdisk -l" >> >> Device Boot Start End Blocks Id System >> disk.img1 * 1 13 104391 83 Linux >> disk.img2 14 2491 19904535 8e Linux LVM >> >> Now I can loopback mount the first bartition using >> "mount -o loop,offset=32256 disk.img /mnt". >> >> I need to mount the second partition. If the secoond partition had >> been an ext3 partition, I would have loopback mounted it as >> "mount -o loop,offset=$((255*63*512*13) disk.img /mnt", but when I try >> that, I get >> mount: unknown filesystem type 'LVM2_member' >> >> Any help is greatly appreciated. > > losetup /dev/loop0 disk.img > kpartx -a /dev/loop0 > > Then to mount the first partition: > > mount /dev/mapper/loop0p1 /mnt > > Or to activate the volume group then mount the logical volume: > > vgscan > vgchange -ay vg > mount /dev/vg/lv /mnt > > Hope that helps. > > --Dave > > > > ------------------------------ > > Message: 4 > Date: Mon, 9 Jun 2008 11:44:53 +0200 > From: Heinz Mauelshagen <mauelshagen@redhat.com> > Subject: Re: Performance tunning on LVM2 > To: LVM general discussion and development <linux-lvm@redhat.com> > Message-ID: <20080609094453.GA5507@redhat.com> > Content-Type: text/plain; charset=us-ascii > > On Fri, Jun 06, 2008 at 08:03:51AM -0700, Larry Dickson wrote: >> A (linear) volume group made of two physical volumes consists of one PV >> followed by the other, rather like a "Raid-Linear". If you size the >> origin logical volume right, you can get one LV (the origin) to fall on one >> disk, and force the snapshot to land on the other disk. This eliminates >> back-and-forth seeking to the COW. Whether it solves your problem will >> depend on how smart the driver is about the read-before-write activity on >> the origin volume. >> >> Other members of the list may have more experience on this. Comments? > > If I read correctly, Antony just has *ONE* PV. > > So no matter what, he has to add another to allow for snapshot COW > store allocation on that other PV, distinct from the one holding > the origin(s). Presumably there's no other bottleneck aside from the > disk, that'll do better. > > Keep in mind, that unless you've got streaming writes, the performance > won't drop as much as in the (artificial) dd test below. > > FYI: With the current snapshot implementation, multiple snapshots per single > origin will throttle write performance because of write duplication > to all per snapshot COW stores. > > Heinz > >> >> Larry >> >> On 6/6/08, Antony MARTINEAU <Antony.MARTINEAU@lippi.fr> wrote: >> > >> > >> > 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* <antony.martineau@lippi.fr>* >> > **http://www.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*<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* <http://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* <antony.martineau@lippi.fr>* >> > **http://www.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* <http://www.lippi.fr/disclaimer.php> >> > >> > 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* <http://www.lippi.fr/disclaimer.php> >> > >> > >> > _______________________________________________ >> > linux-lvm mailing list* >> > **linux-lvm@redhat.com* <linux-lvm@redhat.com>* >> > **https://www.redhat.com/mailman/listinfo/linux-lvm*<https://www.redhat.com/mailman/listinfo/linux-lvm> >> > read the LVM HOW-TO at *http://tldp.org/HOWTO/LVM-HOWTO/*<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* <http://www.lippi.fr/disclaimer.php> >> > >> > 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* <http://www.lippi.fr/disclaimer.php> >> > >> > >> > _______________________________________________ >> > 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/ > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > > Heinz Mauelshagen Red Hat GmbH > Consulting Development Engineer Am Sonnenhang 11 > Storage Development 56242 Marienrachdorf > Germany > Mauelshagen@RedHat.com PHONE +49 171 7803392 > FAX +49 2626 924446 > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > > > > ------------------------------ > > Message: 5 > Date: Mon, 9 Jun 2008 12:06:19 +0200 > From: Antony MARTINEAU <Antony.MARTINEAU@lippi.fr> > Subject: Re: Performance tunning on LVM2 > To: mauelshagen@redhat.com, LVM general discussion and development > <linux-lvm@redhat.com> > Message-ID: > <OF8D53F89C.8A8CDA30-ONC1257463.00362B8A-C1257463.00377B47@lippi.fr> > Content-Type: text/plain; charset="us-ascii" > > Skipped content of type multipart/alternative-------------- next part -------------- > A non-text attachment was scrubbed... > Name: not available > Type: image/gif > Size: 5552 bytes > Desc: not available > Url : https://www.redhat.com/archives/linux-lvm/attachments/20080609/c6399248/attachment.gif > > ------------------------------ > > _______________________________________________ > linux-lvm mailing list > linux-lvm@redhat.com > https://www.redhat.com/mailman/listinfo/linux-lvm > > End of linux-lvm Digest, Vol 52, Issue 9 > **************************************** > _______________________________________________ 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/
