Specifications

Table 27. LUN limitations for various components (continued)
System component LUN limit
Host bus adapter 256
ESS 960 (15 target IDs times 64 LUNs)
SAN Data Gateway 255
Table 27 on page 169 shows a maximum LUN limit of 120 because it is the lowest
number supported by one of the components.
However, fixes are available to eliminate problems and limitations. For example,
Service Pack 4 and above already supports up to 256 devices.
The following shows the details of the Ethernet port and the service port:
Ethernet
10BASE-T port for out-band management (using StorWatch SAN Data
Gateway Specialist)
Service port
9-pin D-shell connector for local service, configuration, and diagnostics
The SAN Data Gateway supports channel zoning and LUN masking between fibre
channel ports and SCSI ports. Channel zoning and masking enable you to specify
which fibre-channel hosts can connect to the LUNs that are defined on SCSI ports.
This is important if you do not want multiple host systems accessing the same
LUNs.
Migrating volumes from the SAN Data Gateway to native fibre-channel
The steps to migrate from a SAN Data Gateway to fibre-channel are similar to the
steps to migrate from native SCSI to fibre-channel.
Perform the following steps on the ESS to migrate volumes from the SAN Data
Gateway to native fibre channel:
1. Use the ESS Specialist to define the new fibre-channel host bus adapter to the
ESS.
2. Assign the volumes to the newly defined host. In practice, this means assigning
the volumes to the worldwide port name of the host adapter.
3. Unassign the volumes from the SCSI host.
This procedure assumes that there is a spare slot in the ESS host bays for the
fibre-channel adapter to coexist with the SCSI adapter. If the SCSI adapter has to
be removed before you can install the the fibre-channel adapter, you must list the
volume assignments before you remove the SCSI adapter.
170 ESS Host Systems Attachment Guide