HP Surestore Disk Array 12h - And FC60, Advanced User'S Manual, Page: 298 / 466

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Managing the Disk Array Using Array Manager 60
Managing the Universal Transport Mechanism (UTM)
On firmware HP08 and later, the Universal Transport Mechanism (UTM) serves as the SCSI
communication path between the host and the disk array. In earlier versions of firmware,
this communication was done using LUN 0. The UTM is configured as a separate LUN,
which is used only for communication and not for storing data. Because it consumes one of
the available LUNs, only 31 LUNs are available when using the UTM. Any attempt to
perform an I/O to the UTM LUN will be rejected.
The UTM is enabled by default and configured as LUN 31. It is possible to change the LUN
used for the UTM to something other than 31. When upgrading to HP08 firmware on a disk
array that already has LUN 31 defined, it will be necessary to copy the data a new LUN and
delete LUN 31 before downloading the HP08 firmware.
One of the primary benefits of using the UTM is Major Event Logging (MEL). If the UTM is
disabled, major event logging will not be performed. Instead, the standard controller logs
will be used to gather disk array status. Because of the benefits it offers, it is recommended
that the UTM be enabled.
Enabling and Changing the UTM LUN
LUN 31 is assigned as the default LUN used for the UTM. In most cases this should be
acceptable. It is possible to change the LUN used for the UTM if you wish to do so. This
command is also used to enable the UTM if it is disabled.
Note
LUN 0 cannot be used for the UTM.
To change the LUN number used for UTM, or to enable the UTM, type:
ammgr -U -l <LUN> <ArrayID>
•
LUN identifies the default LUN that will be used for the ATM. This value is stored in
controller NVSRAM. If
LUN is not specified, the default value currently stored in
NVSRAM will be used for the ATM. The UTM will be enabled if it is currently disabled.