HP XC System Software Release Notes for Version 3.1

infrastructure allows you the flexibility to select and use the availability tool you prefer to manage
the services.
In this release, HP Serviceguard is the recommended availability tool, and it must be purchased
and licensed separately from HP.
In general, availability tools monitor nodes, services and resources, and restart the services and
resources on another node, as necessary. In most cases, IP aliases are used for the failover of
services so that client nodes can continue to communicate with an IP address. The client nodes
do not detect that the actual node has changed.
HP has supplied translator and other essential scripts for HP Serviceguard for you. The translator
and scripts obtain the availability information in the configuration and management database
and create the appropriate HP Serviceguard configuration files. When you install the Serviceguard
RPM from the HP XC DVD, the HP Serviceguard scripts are loaded into the
/opt/hptc/availability/serviceguard directory. This RPM enables Serviceguard to
operate on an HP XC system.
Any availability tool you decide to use must be installed on the head node before invoking the
cluster_config utility.
Defining an availability solution requires advance planning. You must determine in advance the
services for which you want to enable improved availability and which nodes will be assigned
with those services. Then, you must ensure that you assign the appropriate roles to the nodes
defined in the availability set.
New Commands Associated with Improved Availability The following commands have been
added to the HP XC command suite to support improved availability:
• transfer_to_avail turns over service management responsibilities to the appropriate
availability tool or tools
• transfer_from_avail returns service management responsibilities to HP XC commands
rather than the availability tool or tools
New Functionality Provided by the /sbin/service Script When improved availability is configured,
the behavior of the /sbin/service script differs as follows: a filter script handles services that
are being managed by the availability tool differently than standard services. Services with
improved availability are stopped, started, restarted and provide status through the availability
tool, not through the standard service script mechanisms. All other /sbin/service commands
are processed by the standard service script.
How to plan a service availability strategy and configure availability sets is documented in the
HP XC System Software Installation Guide.
1.5 Support for Software RAID-0 and RAID-1
The ability to enable software RAID-0 (striping) on client nodes or software RAID-1 (mirroring)
on the head node and client nodes has been added in this release.
Software RAID-0 enables client nodes that have more than one storage disk to split data evenly
across the disks. Striping is typically used to increase performance. However, because there is
no parity information for redundancy, reliability is reduced. A single disk failure affects both
disks. Software RAID-0 is not supported on the head node.
Software RAID-1 enables nodes that have more than one storage disk to increase reliability by
maintaining a redundant (mirrored) disk copy. When a node is imaged with RAID-1 support,
the entire disk is mirrored. If a disk fails, nodes can continue to run using the other disk.
The procedure that describes how to enable software RAID is documented in the HP XC System
Software Installation Guide.
20 New and Changed Features