HP Serviceguard Storage Management Suite Version A.02.00 for HP-UX 11i v2 Release Notes, September 2008

SCSI-3 Persistent Reservation Support
Veritas Cluster Server (VCS) relies on SCSI-3 Persistent Reservation being supported on the
storage. This is part of the Veritas split brain prevention. HP Serviceguard uses a different and
more robust method to prevent split brain, there is no need for SCSI-3 Persistent Reservation on
the storage.
Use of HP-UX mount Commands for CFS Environments
Once the disk group and mount point multi-node packages are created in Serviceguard, it is
critical to use the CFS commands, including cfsdgadm, cfsmntadm, cfsmount, and
cfsumount. If the HP-UX commands such as mount and umount are used, it could cause serious
problems such as writing to the local file system instead of the cluster file system.
Any form of the HP-UX mount command (for example, mount -o cluster,
dbed_chkptmount, orsfrac_chkptmount) in a HP Serviceguard Storage Management Suite
bundle environment with CFS should be done with caution. These non-CFS commands could
cause conflicts with subsequent CFS command operations on the file system or Serviceguard
packages. Use of these forms of mount will not create an appropriate multi-node package which
means that the cluster packages are not aware of the file system changes. Instead, use the CFS
commands cfsmount or cfsumount.
Dirty Region Logging (DRL) for Mirrored Volumes
If a system failure occurs while mirrored volumes are in use, the mirrors will recover and clean
up any writes that were in progress when the system failed. The Dirty Region Logging (DRL)
feature tracks writes that are in progress to reduce the recovery effort after a system failure.
Without DRL, the entire volume must be recovered, because there is no way to determine which
blocks had writes in progress at the time of the system failure. The recovery operation is I/O
intensive and can be time consuming, depending on the number of volumes and how large they
are. In a clustered environment the IO performance of multiple nodes using the same volume
will be impacted during recovery. HP strongly recommends that you use DRL with mirrored
data volumes in a clustered environment to enable faster volume recovery. However, Oracle
database volumes should be configured without DRL, because the Oracle database application
keeps its own logs and does not require VxVM to maintain logs. For information on DRL and
the Veritas™ SmartSync Recovery Accelerator, see the Veritas Volume Manager 5.0 Administrator’s
Guide.
HP-UX Operating Environment Upgrade Limitations
When you purchase an HP Serviceguard Storage Management Suite (SG SMS) Operating
Environment (OE) bundle, the SG SMS software is provided on one DVD and the HP-UX OE
(Mission Critical - MCOE, Data Center - DCOE, or High Availability - HAOE) is provided on a
separate DVD.
The software provided on the SG SMS DVD relies on products and filesets that are provided on
the OE DVD, including HP Serviceguard and the Veritas Storage Foundation products. Each SG
SMS version relies on specific versions of HP Serviceguard and the Veritas Storage Foundation
products that can change with new OE releases.
The software on the SG SMS DVD is installed using swinstall. If an HP-UX OE is installed on
your system and you attempt to install a SG SMS version that is not supported with the versions
of Serviceguard and Veritas Storage Foundation included with the OE, swinstall will detect
the incompatible software and the installation will fail.
The software on the OE DVD is installed using update-ux. If a SG SMS bundle is installed on
your system and you attempt to install or upgrade to an OE version that includes Serviceguard
and Veritas Storage Foundation versions that are not supported with the SG SMS bundle,
update-ux will not detect the incompatible software. The installation will complete, but the
26 HP Serviceguard Storage Management Suite Version A.02.00 Release Notes