Infortrend RAID Controller Manual

9-16
Figure 9 - 5 Host-LUN Mapping
Creating LUN Masks
User can configure the storage subsystem to appear as 32 LUNs per
Fibre target ID. Each LUN can be mapped with a storage unit -a
partition or the entire logical drive. The configuration of logical units
depends on host applications and how many drives and drive
channels have been employed in the storage system.
The diagram below shows the idea of the virtual connection and the
physical connection between storage and host computers. There are
multiple host computers connected across a storage network and a
system administrator may want to make each storage unit available
for certain host systems while forbidden from some others.
Figure 9 - 6 LUN Mask
The access control can also be implemented by filter drivers.
However, comparing to the control by software, access control based
on controller LUN mapping can avoid overheads on server and the
additional I/O latency. The LUN map combines Host ID (in the Fibre
case, a 64-bit "port name;" in the SCSI case, the initiator ID) with the
list of attributes of a LUN map that originally only consisted of the
channel, target ID, and the LUN number.
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