Hi Coates, Thanks for the information.I am close to the solution now. >>Once you assembled the multipath devices you can then run pvcreate /dev/mapper/XXXXX and create your volume groups. But the only thing i am unable to understand is that how would I assemble the multipath device? who will do this for us LVM2 or Device mapper and how? What are the steps I need to follow? What argument should I provide to pvcreate as I had already filtered "sd" devices? How would I create my assembled device "/dev/mapper/XXXXX"? It would be very helpful if you could tell me what are the steps to create assembled device "/dev/mapper/XXXXX". How this assembled device is mapped to the underlying "sd" devices? Regards Shahid Shaikh. -----Original Message----- From: Guy Coates [mailto:gmpc@xxxxxxxxxxxx] Sent: Wednesday, February 16, 2005 7:53 PM To: shahid.shaikh@xxxxxxxxx; device-mapper development Cc: Christophe Varoqui (E-mail); Sandhya Suman (E-mail) Subject: Re: [dm-devel] Detecting Multiple Paths to LU You need to set up lvm.conf to do the following. It probably is totally correct, but it seems to work well enough. # Make lvm look at the multipath device maps only, not the # single devices scan = [ "/dev/mapper" ] # exclude the raw disks, just to be paranoid filter = ["r|/dev/sd|"] # make lvm use dm devices types = [ "device-mapper", 16 ] Once you assembled the multipath devices you can then run pvcreate /dev/mapper/XXXXX and create your volume groups. I've created and then extended and LVM across two multipathed physical volumes on my test system. --- Volume group --- VG Name web409mysqltest System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 4 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 1 Max PV 0 Cur PV 2 Act PV 2 VG Size 199.99 GB PE Size 4.00 MB Total PE 51198 Alloc PE / Size 51198 / 199.99 GB Free PE / Size 0 / 0 VG UUID CzUDTb-KpRz-KNLS-U24P-5TmZ-4WLN-OSjGBB --- Logical volume --- LV Name /dev/web409mysqltest/mysqltest1 VG Name web409mysqltest LV UUID tT9PHO-1UVt-RsNN-6iFM-KgQx-Gl9r-adck9U LV Write Access read/write LV Status available # open 2 LV Size 199.99 GB Current LE 51198 Segments 2 Allocation inherit Read ahead sectors 0 Block device 254:16 --- Physical volumes --- PV Name /dev/mapper/3600508b40001417e0001c00001b60000 PV UUID 3QvL3p-t45P-AY4x-nIHp-C44s-IM6O-2Ymuwy PV Status allocatable Total PE / Free PE 25599 / 0 PV Name /dev/mapper/3600508b40001417e0001c00001c90000 PV UUID QGEVaA-W3sJ-DkLB-Ble1-13sU-bL6u-3tNy78 PV Status allocatable Total PE / Free PE 25599 / 0 /sbin/dmsetup status /dev/mapper/3600508b40001417e0001c00001c90000 0 209715200 multipath 1 0 0 2 2 E 0 2 0 65:240 A 0 8:176 A 0 E 0 2 0 8:16 A 0 65:80 A 0 /sbin/dmsetup status /dev/mapper/3600508b40001417e0001c00001b60000 0 209715200 multipath 1 0 0 2 2 E 0 2 0 65:224 A 0 8:160 A 0 E 0 2 0 8:0 A 0 65:64 A 0 lvm version report lvm version LVM version: 2.00.24 (2004-09-16) Library version: 1.00.19-ioctl (2004-07-03) Driver version: 4.3.0 Guy -- Dr. Guy Coates, Informatics System Group The Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK Tel: +44 (0)1223 834244 ex 7199 http://www.patni.com World-Wide Partnerships. World-Class Solutions. _____________________________________________________________________ This e-mail message may contain proprietary, confidential or legally privileged information for the sole use of the person or entity to whom this message was originally addressed. Any review, e-transmission dissemination or other use of or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you have received this e-mail in error kindly delete this e-mail from your records. If it appears that this mail has been forwarded to you without proper authority, please notify us immediately at netadmin@xxxxxxxxx and delete this mail. _____________________________________________________________________ http://www.patni.com World-Wide Partnerships. World-Class Solutions. _____________________________________________________________________ This e-mail message may contain proprietary, confidential or legally privileged information for the sole use of the person or entity to whom this message was originally addressed. Any review, e-transmission dissemination or other use of or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you have received this e-mail in error kindly delete this e-mail from your records. If it appears that this mail has been forwarded to you without proper authority, please notify us immediately at netadmin@xxxxxxxxx and delete this mail. _____________________________________________________________________