active dual controllers in HP-UX environments (400677-002, October 2006)

Migrating from an active/passive single controller to active/active dual controllers in HP-UX environments 5

Overview

This document outlines the required steps to migrate existing HP-UX MSA1000 or MSA1500 environments

from a single-controller MSA using active/passive controller firmware to a dual-controller MSA using

active/active controller firmware.

Active/active features:

• Supports simultaneous I/O processing on the controllers, providing better performance as well as high

availability. (I/O can be processed simultaneously by both controllers, but the LUNs are owned by only

one controller at any given time.)

• Supports explicit controller ownership using the MSA Command Line Interface (CLI).

• Supports implicit LUN failover to the other controller for optimized I/O processing for HP-UX PVLinks.

Active/active limitations:

• The MSA supports a maximum of 32 LUNs.

• PVLinks supports a maximum of 8 paths per LUN.

• SecurePath v3.0f SP2 supports a maximum of 32 paths per LUN.

Preparing for the migration

NOTE: Before proceeding with the upgrade, understand the following:

• The coexistence of active/active and active/passive storage systems on the same host may not be

supported. See the MSA1000 or MSA1500 web site for the latest support statement.

• Be sure to assess the impact of the upgrade on all hosts and storage devices before proceeding with

this upgrade.

• Single-controller configurations are no longer supported; two controllers must be installed in the MSA.

• Before installing the additional array controller, ensure that both controllers have the same cache size

installed. (MSA1000 environments must have 256MB or greater cache modules installed; 128MB

cache modules are not supported in MSA1000 active/active environments.)

• It is not possible to migrate back to active/passive firmware. Re-loading the older firmware will result in

the loss of all configuration information on the MSA.

• Due to the required MSA and possible server restarts, a scheduled maintenance window of

approximately one hour (in addition to time required to perform the backups) is needed to complete the

migration.

• During the migration process, do not change the SAN configuration:

• Do not move from a direct-connect configuration to a switched-fabric connection; instead, make this

change after completing the migration.

• Do not move the target Fibre Channel cable from one port on a fabric switch to another port.

• Do not change the switch domain.

CAUTION: A full backup of the HP-UX operating system files and data volumes is highly recommended

before starting the upgrade process. HP is not responsible for data loss incurred during the upgrade

process.

MSA web sites

The following MSA web sites are accessed during these migration procedures:

• MSA1500 web site: http://www.hp.com/go/msa1500cs

• MSA1000 web site: http://www.hp/com/go/msa1000