I'm trying to setup a LVM mirror on 2 iSCS targets, but can't.

I have added both /dev/sda & /dev/sdb to the LVM-RAID PV, and both have 500GB space.

[root@HP-DL360 by-path]# pvscan PV /dev/cciss/c0d0p2 VG LVM lvm2 [136.59 GB / 2.69 GB free] PV /dev/sda VG LVM-RAID lvm2 [500.00 GB / 490.00 GB free] PV /dev/sdb VG LVM-RAID lvm2 [502.70 GB / 492.70 GB free] Total: 3 [1.11 TB] / in use: 3 [1.11 TB] / in no VG: 0 [0 ]

[root@HP-DL360 by-path]# vgscan Reading all physical volumes. This may take a while... Found volume group "LVM" using metadata type lvm2 Found volume group "LVM-RAID" using metadata type lvm2

I can add a single LVM volume:

[root@HP-DL360 by-path]# lvscan ACTIVE '/dev/LVM/root' [10.00 GB] inherit ACTIVE '/dev/LVM/swap' [3.91 GB] inherit ACTIVE '/dev/LVM/data' [120.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol0' [10.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol1' [10.00 GB] inherit [root@HP-DL360 by-path]# lvcreate -L 10G LVM-RAID Logical volume "lvol2" created

Yet, when I try and add a mirror, I get this:

[root@HP-DL360 by-path]# lvcreate -L 10G -m1 LVM-RAID Insufficient suitable allocatable extents for logical volume : 2560 more required Unable to allocate extents for mirror(s).

I can create a stripe though:

[root@HP-DL360 by-path]# lvcreate -L 20G -i2 -I64 LVM-RAID Logical volume "lvol3" created [root@HP-DL360 by-path]# lvscan ACTIVE '/dev/LVM/root' [10.00 GB] inherit ACTIVE '/dev/LVM/swap' [3.91 GB] inherit ACTIVE '/dev/LVM/data' [120.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol0' [10.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol1' [10.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol2' [10.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol3' [20.00 GB] inherit

I could even create a large stripe:

[root@HP-DL360 by-path]# lvcreate -L 600G -i2 -I64 LVM-RAID Logical volume "lvol4" created [root@HP-DL360 by-path]# lvscan ACTIVE '/dev/LVM/root' [10.00 GB] inherit ACTIVE '/dev/LVM/swap' [3.91 GB] inherit ACTIVE '/dev/LVM/data' [120.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol0' [10.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol1' [10.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol2' [10.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol3' [20.00 GB] inherit ACTIVE '/dev/LVM-RAID/lvol4' [600.00 GB] inherit [root@HP-DL360 by-path]# pvscan PV /dev/cciss/c0d0p2 VG LVM lvm2 [136.59 GB / 2.69 GB free] PV /dev/sda VG LVM-RAID lvm2 [500.00 GB / 180.00 GB free] PV /dev/sdb VG LVM-RAID lvm2 [502.70 GB / 172.70 GB free] Total: 3 [1.11 TB] / in use: 3 [1.11 TB] / in no VG: 0 [0 ]

But, the mirror keeps failing:

[root@HP-DL360 by-path]# lvcreate -L 10G -m1 LVM-RAID Insufficient suitable allocatable extents for logical volume : 2560 more required Unable to allocate extents for mirror(s).

This is on CentOS 5.5 x64

[root@HP-DL360 by-path]# cat /etc/redhat-release CentOS release 5.5 (Final) [root@HP-DL360 by-path]# uname -a Linux HP-DL360 2.6.18-194.32.1.el5xen #1 SMP Wed Jan 5 18:44:24 EST 2011 x86_64 x86_64 x86_64 GNU/Linux

Does anyone know why this happens?