P.S. When I run pvscan I get this output: root@storage:~# pvscan /dev/sdc: read failed after 0 of 4096 at 0: Input/output error /dev/sdc: read failed after 0 of 4096 at 214748299264: Input/output error /dev/sdc: read failed after 0 of 4096 at 0: Input/output error /dev/sdd: read failed after 0 of 4096 at 0: Input/output error /dev/sdd: read failed after 0 of 4096 at 214748299264: Input/output error /dev/sdd: read failed after 0 of 4096 at 0: Input/output error /dev/sdf: read failed after 0 of 4096 at 0: Input/output error /dev/sdf: read failed after 0 of 4096 at 214748299264: Input/output error /dev/sdf: read failed after 0 of 4096 at 0: Input/output error /dev/sdi: read failed after 0 of 4096 at 0: Input/output error /dev/sdi: read failed after 0 of 4096 at 214748299264: Input/output error /dev/sdi: read failed after 0 of 4096 at 0: Input/output error PV /dev/dm-0 VG VG_XenStorage-755d6649-e770-6f01-5e17-fd7f8dcd8651 lvm2 [199.99 GB / 185.49 GB free] Total: 1 [199.99 GB] / in use: 1 [199.99 GB] / in no VG: 0 [0 ] So here it does see the dm-0? Please advice... Sander On Mon, 2007-11-19 at 09:22 -0800, malahal@xxxxxxxxxx wrote: > Tore Anderson [tore@xxxxxxxxx] wrote: > > * S. J. van Harmelen > > > > > I have a couple of LUN's that are handled by the multipath driver. > > > This works great, but now I want to use LVM so I can take snapshots > > > of one LUN to another LUN. > > > > > > Can someone tell me how to do this? > > > > > > When I do pvcreate /dev/mapper/diskname I get an error that the disk > > > is already part of an volume group. But I sertainly did not configure > > > that. > > > > > > Can it be that the multipath driver of devmapper did that? > > > > If you have a PV signature on the volume, LVM might have used one of the > > paths instead of using the multipath'ed device under /dev/mapper. You > > should be able to check this by running the command "pvs" - it should > > list all the detected PVs on your system. > > If LVM uses single pathed disks like /dev/sda, then multipath can't use > the same path to make a multipathed device, right? My guess is that > /dev/mapper/multipath-name is indeed part of the LVM in your case. I > would like to know what happened otherwise. Thank you. > > --Malahal. > > -- > dm-devel mailing list > dm-devel@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/dm-devel -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel