Managing HP Serviceguard A.11.20.20 for Linux, March 2014

• A maximum of 30 network interfaces per node is supported. The interfaces can be physical
NIC ports, VLAN interfaces, Channel Bonds, or any combination of these.
• Only port-based and IP-subnet-based VLANs are supported. Protocol-based VLAN is not
supported because Serviceguard does not support any transport protocols other than TCP/IP.
• Each VLAN interface must be assigned an IP address in a unique subnet.
• Using VLAN in a Wide Area Network cluster is not supported.
3.5.11.4 Additional Heartbeat Requirements
VLAN technology allows great flexibility in network configuration. To maintain Serviceguard’s
reliability and availability in such an environment, the heartbeat rules are tightened as follows
when the cluster is using VLANs:
1. VLAN heartbeat networks must be configured on separate physical NICs or Channel Bonds,
to avoid single points of failure.
2. Heartbeats are still recommended on all cluster networks, including VLANs.
3. If you are using VLANs, but decide not to use VLANs for heartbeat networks, heartbeats are
recommended for all other physical networks or Channel Bonds specified in the cluster
configuration file.
3.6 Volume Managers for Data Storage
A volume manager lets you create units of disk storage that are more flexible than individual disk
partitions. These units can be used on single systems or in high-availability clusters. HP Serviceguard
for Linux uses the Linux Logical Volume Manager (LVM) which creates redundant storage groups.
This section provides an overview of volume management with LVM. See “Creating the Logical
Volume Infrastructure ” (page 145) in Chapter 5 for information about configuring volume groups,
logical volumes, and file systems for use in Serviceguard packages.
In HP Serviceguard for Linux, the supported shared data storage type is disk arrays which configure
redundant storage in hardware.
In a disk array, the basic element of storage is a LUN, which already provides storage redundancy
via RAID1 or RAID5. Before you can use the LUNs, you must partition them using fdisk.
In LVM, you manipulate storage in one or more volume groups. A volume group is built by grouping
individual physical volumes. Physical volumes can be disk partitions or LUNs that have been marked
as physical volumes as described below.
You use the pvcreate command to mark the LUN as physical volumes. Then you use the vgcreate
command to create volume groups out of one or more physical volumes. Once configured, a
volume group can be subdivided into logical volumes of different sizes and types. File systems or
databases used by the applications in the cluster are mounted on these logical volumes. In
Serviceguard clusters, volume groups are activated by package control scripts when an application
starts up, and they are deactivated by package control scripts when the application halts.
3.6.1 Storage on Arrays
Figure 26 shows LUNs configured on a storage array. Physical disks are configured by an array
utility program into logical units, or LUNs, which are seen by the operating system.
3.6 Volume Managers for Data Storage 71