Managing Serviceguard 12th Edition, March 2006

Understanding Serviceguard Hardware Configurations
Redundant Disk Storage
Chapter 244
Redundant Disk Storage
Each node in a cluster has its own root disk, but each node is also
physically connected to several other disks in such a way that more than
one node can obtain access to the data and programs associated with a
package it is configured for. This access is provided by a Storage
Manager, such as Logical Volume Manager (LVM), VERITAS Volume
Manager (VxVM), or VERITAS Cluster Volume Manager (CVM). LVM
and VxVM disk storage groups can be activated by no more than one
node at a time, but when a failover package is moved, the storage group
can be activated by the adoptive node. All of the disks in the storage
group owned by a failover package must be connected to the original
node and to all possible adoptive nodes for that package. Disk storage is
made redundant by using RAID or software mirroring.
Supported Disk Interfaces
The following interfaces are supported by Serviceguard for disks that are
connected to two or more nodes (shared data disks):
• Single-ended SCSI
•SCSI
•Fibre Channel
Not all SCSI disks are supported. See the HP Unix Servers Configuration
Guide (available through your HP representative) for a list of currently
supported disks.
NOTE In a cluster that contains systems with PCI SCSI adapters, you cannot
attach both PCI and NIO SCSI adapters to the same shared SCSI bus.
External shared Fast/Wide SCSI buses must be equipped with in-line
terminators for disks on a shared bus. Refer to the “Troubleshooting”
chapter for additional information.
When planning and assigning SCSI bus priority, remember that one
node can dominate a bus shared by multiple nodes, depending on what
SCSI addresses are assigned to the controller for each node on the