Managing HP Serviceguard A.12.00.00 for Linux, June 2014

You can build a cluster (next section) before or after defining volume groups for shared data
storage. If you create the cluster first, information about storage can be added to the cluster and
package configuration files after the volume groups are created.
See “Volume Managers for Data Storage” (page 69) for an overview of volume management in
HP Serviceguard for Linux. The sections that follow explain how to do the following tasks:
• Displaying Disk Information (page 154)
• Creating Partitions (page 155)
• Enabling Volume Group Activation Protection (page 156)
• Building Volume Groups: Example for Smart Array Cluster Storage (MSA 2000 Series)
(page 157)
• Building Volume Groups and Logical Volumes (page 158)
• Testing the Shared Configuration (page 159)
• Storing Volume Group Configuration Data (page 160)
• Setting up Disk Monitoring (page 161)
CAUTION: The minor numbers used by the LVM volume groups must be the same on all cluster
nodes. This means that if there are any non-shared volume groups in the cluster, create the same
number of them on all nodes, and create them before you define the shared storage. If possible,
avoid using private volume groups, especially LVM boot volumes. Minor numbers increment with
each logical volume, and mismatched numbers of logical volumes between nodes can cause a
failure of LVM (and boot, if you are using an LVM boot volume).
NOTE: Except as noted in the sections that follow, you perform the LVM configuration of shared
storage on only one node. The disk partitions will be visible on other nodes as soon as you reboot
those nodes. After you’ve distributed the LVM configuration to all the cluster nodes, you will be
able to use LVM commands to switch volume groups between nodes. (To avoid data corruption,
a given volume group must be active on only one node at a time).
For multipath information, see ???.
Limitation
• Multipathing in Serviceguard is supported only with mapper devices. The cmpreparestg
also supports multipathing only with mapper devices. If not, the cmpreparestg might fail
to configure the LVM volume group.
For example, if a device has two paths /dev/sdx and /dev/sdy, the cmpreparestg
might fail to create the LVM volume group. Instead, if mapper device /dev/mapper/mpathx
is configured for dev/sdx, the cmpreparestg creates the LVM volume group.
5.1.12.1 Displaying Disk Information
To display a list of configured disks, use the following command:
fdisk -l
You will see output such as the following:
Disk /dev/sda: 64 heads, 32 sectors, 8678 cylinders
Units = cylinders of 2048 * 512 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 1001 1025008 83 Linux
/dev/sda2 1002 8678 7861248 5 Extended
/dev/sda5 1002 4002 3073008 83 Linux
/dev/sda6 4003 5003 1025008 82 Linux swap
/dev/sda7 5004 8678 3763184 83 Linux
Disk /dev/sdb: 64 heads, 32 sectors, 8678 cylinders
154 Building an HA Cluster Configuration