HP Serviceguard Extended Distance Cluster for Linux A.01.01 Deployment Guide, Third Edition, May 2008

Configuring your Environment for Software RAID
Creating Volume Groups and Configuring VG Exclusive Activation on the MD Mirror
Chapter 372
Creating Volume Groups and Configuring VG
Exclusive Activation on the MD Mirror
Once you create the MD mirror device, you need to create volume groups
and logical volumes on it.
NOTE XDC A.01.01 does not support configuring multiple raid1 devices as
physical volumes in a single volume group.
For example, if you create a volume group vg01, it can have only one MD
raid1 device /dev/md0 as its physical volume. To configure multiple raid1
devices as physical volumes in a single volume group, you must install
the XDC A.01.02 patch.
XDC A.01.02 contains the following patches for Red Hat and SuSE Linux
operating systems:
• SGLX_00133 for Red Hat Enterprise Linux 4
• SGLX_00134 for Red Hat Enterprise Linux 5
• SGLX_00135 for SUSE Linux Enterprise Server 10
You can contact the HP support personnel to obtain these patches.
Creating the volume group and logical volume infrastructure on an MD
device is similar to creating the same on a single device. However, when
you create a logical volume on an MD device, it can be done on a physical
disk (LUN) or on a partition.
For example - Let us assume that /dev/sde and /dev/sdf are two
physical disks that form the md device /dev/md0. The persistent device
names for /dev/sde and /dev/sdf are /dev/hpdev/md0_mirror0 and
/dev/hpdev/md0_mirror1 respectively. When you create a logical
volume, duplicate entries are detected for the two physical disks that
form the mirror device. As a result, the logical volume is not created and
an error message is displayed. Following is a sample of the error message
that is displayed:
Found duplicate PV 9w3TIxKZ6lFRqWUmQm9tlV5nsdUkTi4i: using
/dev/sde not /dev/sdf