HP StorageWorks Enterprise Virtual Array Online Firmware Upgrade Best Practices (5697-6388, January 2007)

Large block transfers
Unlike small block transfers, when the workload on the storage system is dominated by large b lock I/O s
the workload capacity of the storage system is best monitored in terms of the throughput as measured in
megabytes per second or MB/s. Large block sequential workloads are typical of b ackup and restore
operations.
Figu
re 8 Large block transfer profile
Recommendations for upgrading a busy storage system
In some enviro nm ents there may not be a period when the storage system load is low enough to safely
perform an online firmware upgrade. In this situation there are two a lternatives:
• Perform an offline upgrade. Scheduled downtime can be used to perform the upgrade when
convenient. This will delay use of the benefits and enhancements included in the new firmware
release.
• Use HP Command View EVAPerf statistics to identify very active virtual disks, and then halt only
the application(s) imposing the heavy workload. Other applications can remain online during
the firmware upgrade. This method has significantly less impact on the SAN than performing
an offline upgrade.
For example, ana lysis may reveal that a virtual disk is very busy during a particular time b ecause a
host is using that virtual disk to per form backups. The identified host’s backup application can taken
offline, reducing the storage system load to a point where an online upgrades can be safely done.
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Evaluating the SAN for an online upgrade