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

1 Understanding the online
firm ware upgrade process
During the life of an EVA storage system, it will be necessary to periodically upgrade the system firmware.
Upgradingtothemostcurrentfirmware release ensures that the storage system benefits from ongoing
design improvements and enhancements.
Performing the firmware upgrade online minimizes the impact on the hosts and applications accessing
the storage system. It is not necessary to halt I/O or suspend operation of the hosts. Because of the
significant benefits offered by the online upgrade, every effort should be made to use this feature when
upgrading the storage system firmware.
Online upgrade can be per formed on all operating systems supported by the EVA. In addition, online
upgrade has be en tested successfully with applications such as Oracle, Microsoft SQL Ser ver, and
Microsoft Exchange.
Definition of terms
The following terms are used throughout this document and are defi ned as follows:
• Controll
er resynchronization: The interval during which the storage system controllers are
unavaila
ble to process host I/Os. The SAN environment must be able to accommodate this
interval.
• Offline upgrade: An upgrade process that requires stopping all host I/O to the storage system.
This typ
ically requires all applications and hosts accessing the storage system b e shut down prior
to the fir
mware upgrade. The hosts and applications are restarted after the upgrade is complete.
The EV A
supports this t ype of upgrade.
• Online upgrade: An upgrade process that enables the storage system controller firmwar e to be
upgraded while still receiving host I/Os. The fi rmware on both EVA c ontrollers is upgraded
simultaneously, and the resultant resynchronization makes the storage system inaccessible for a
brief period of time. The resynchronization represents a single disruption to I/Os.
How online upgrade works
The following provides an overview of the major steps involved in the online upgrade process.
1. Download the new firmware image to the controllers.
2. Validate the firmware image and copy it to flash mem ory.
3. In an HP Continuous Access EVA environment, the peer storage system is notifi ed that a
resynchronization will occur.
4. Resynchronize the controllers.
5. Host I/Os not processed by the controllers during the resynchronization is retried by the host
and completed.
Processing of host I/Os continues while the firmware images are downloaded and validated, and while
HP Continuous Access EVA systems are being notified. In most s ituations, the controller resynchronization
interval is less than 40 seconds, which is well below the 60 second timeout allowed by most operating
systems.
HP StorageWorks Enterprise Virtual Array online firmware upgrade best practices
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