McDATA 3000 Manual Do Utilizador

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10
FC/SCSI Tape Pipelining
 
10-5
Dynamic Target LUN Discovery and LUN Mapping
Target discovery is not aware of device type or available LUNs on the 
discovered target.
LUN Discovery
A maximum of 32 devices can be discovered or configured 
unidirectionally per I/O pair. Available bandwidth should be 
considered for concurrent operation of the drives.
As targets are discovered, those targets will be queried for available 
devices via LUN discovery. A configurable number of LUNs 
(maximum of 32, default is 8) will be attempted to be discovered for 
each discovered remote target. These devices will be mapped on the 
Edge target LUN field with the dynamic LUN mapping rules. LUN 
discovery will filter remote LUNs based upon the device type field in 
the inquiry response. Only device types of tape and changers will be 
added to the host LUN table. LUN Discovery is only done to newly 
discovered remote targets.
LUN Refresh
Remote targets will be scanned for newly available LUNs whenever 
the target Edge is rebooted or the user issues the “refresh” command 
via the ttag user interface. If any new LUNs are discovered, those 
LUNs will be added to the host LUN table, if an open host LUN field 
is available. Existing LUNs already discovered to any remote targets 
will not be rescanned. LUN refresh will not remove a remote device 
which is no longer available.
Dynamic LUN 
Mapping
The Edge target will discover, via Edge initiator target discovery, 
available remote targets. The Edge target will map discovered targets 
based upon WWNs on a first learned basis. The discovered targets 
will fill the Edge target LUNs from lowest (1) to highest (x). The 
mapped LUN will be bound to the associated WWN and any change 
in remote target portid will be dynamically learned. The WWN and 
associated Edge target LUN will also be stored onto disk which will 
provide consistency on the Edge target LUN mapping across resets 
and power downs. 
Static LUN Mapping
The Edge target may be configured for a specific Edge target LUN to 
be bound to a designated remote target WWN. If a remote target is 
statically configured, all LUNs to be mapped to that remote target 
must be statically configured and should be mapped consecutively 
from lowest to highest. Any Edge target LUN not statically 
configured will be discovered via dynamic LUN mapping.