EMC Symmetrix DMX-3, Product Manual, Page: 145 / 326

Dynamic Host Addressing 145
Performance and Optimization
Dynamic Host Addressing
Dynamic Host Addressing allows any device seen by any HBA to
have any LUN number, by avoiding fixed LUN offsets. Dynamic
Host Addressing is an enhancement to the VolumeLogix
functionality to provide more flexibility of device addressing on
Symmetrix ports.
VolumeLogix allows users to control which devices on a Symmetrix
port are visible to which HBAs (using the HBA WWN). A previous
feature of Volume Logix, LUN Offset, allowed the user to specify a
single 'offset' for each HBA (for each Symmetrix port) that would be
used to allow HBA's to have their own set of devices visible, starting
at LUN address zero. This was particularly useful for HBAs that
required the use of LUN addresses 0x00-0xFF. LUN Offset was
limited in that it allowed only a single offset to be specified. Since the
LUN address used by the host was directly associated with the
address configured on the FA port, the flexibility of this feature was
limited.
Dynamic Host Addressing provides maximum flexibility when
configuring devices addresses, by removing any association between
the host LUN address and the address given to the device on the FA
port. The only requirement is that the device be mapped to the FA
port. This feature allows any device to be configured for any LUN
address on any originator (HBA) on any port. When configuring new
storage or assigning devices to a port and originator, the user can
either specify the LUN address that the HBA will use to access the
device (for maximum control), or let the system find the next LUN
address available for that HBA (if the user does not require control
over specific LUN addresses).
Dynamic Host Addressing requires a new format of the records in the
VolumeLogix database in the system. Moving to the new format will
be done nondisruptively to the user and transparent overall. On the
first provisioning action that specifies Dynamic Host Addressing
should be used, the record containing the configuration information
for the HBA/Symm port in question will be translated
nondisruptively to the new format. Impact is transparent to the user.
Records in both the old format and the Dynamic Addressing format
can coexist in the system; translation is done only on those records
that are being updated.
Dynamic Host Addressing is supported with SYMCLI version 6.4
and can be managed by Symmetrix Management Console (SMC).