HP SureStore E SAN Manager LUN Management Administrator's Guide

164 Using SAN Manager LM with the FC60 Storage Array
Using SAN Manager LM with the FC60 Storage Array
SAN Manager LM for Windows NT can be used with HP FC60 storage arrays and the RDAC
driver included with the HP Storage Manager 60-NT software.
RDAC is an I/O path failover driver that is installed on host computers that access HP’s
FC60. Typically, a pair of active controllers is located in a storage array. Each volume in the
array is owned by one controller that provides the I/O path. When a component in the I/O
path to the owning controller fails, the RDAC driver transfers ownership of the volumes
assigned to that controller to the other controller in the pair, allowing I/O to proceed.
The communication between the HP Storage Manager 60-NT and RDAC software and the
controllers is done though a special volume (typically LUN 7) that is configured by the
controllers and is called an access volume. Although the access volume is presented as a
unit having limited storage capacity, it is designed to handle only configuration command
transactions using Universal Transport Mechanism (UTM) protocol (not to be confused
with UPM), and cannot be used for standard data storage.
Guidelines for Using RDAC with SAN Manager LM and the FC60
• For failover to work on any given host, the access volume LUNs must be assigned to that
host. HP recommends setting up a share group that includes the storage array
controllers’ access volume LUNs and all of the hosts that are using that RAID and RDAC.
Caution UTM LUNs are not useful as actual storage. Do not try to create a SAN
Manager LM database partition on a UTM LUN.
• The use of Universal Partition Map (UPM) partitions on FC60 storage should generally
be avoided. LUNs with UPM partition maps will not support failover when assigned to
hosts with RDAC. If you have your database on the FC60, you will not have failover for
the SAN Manager database.
Note This will not affect the availability of the database if it was created on a two- or
three-partition mirror set.