Ph. Marek <[EMAIL PROTECTED]> wrote:
> SCSI over IP needs several scsi controllers on one scsi bus.
> is it possible to specify different LUN's but only 1 SCSI ID?
Lets assume you assign SCSI ID 7, LUN 0 to one SCSI host adapter.
You assign SCSI ID 7, LUN 1 to another host adapter. This won't
work, because they have the same SCSI ID, and when the first
selects a device, the second will become confused, to the
least, and will think it's selected (to the worst).
SCSI ID must be unique among the different SCSI chips on the
bus.
So I don't really see an application for LUNs in the IP over
SCSI case.
> It probably doesn't make MUCH sense, because SCSI cables are very limited
> in length, but having more than 8 scsi "devices" on one cable could be
> useful ...
Newer U2 standard offers upto 16 devices per bus. That would make
upto 16 hosts connected by SCSI through their host adapters, directly.
Moreover, the cable length is much longer for U2LVD, I think
15 meters. And the speed is quite interesting (80 MBytes/s, or
8 x Fast Ethernet).
And you can always put two or more SCSI cards on computers to implement
a special topology, ie, say a network where every peer is either
on the same SCSI, or one SCSI hop away (with network stack latency).
This could give 16 computers on SCSI bus 1 (each with two SCSI boards),
and each of the secondary SCSI board (bus 0a to 0g) has 15 additionnal
computers, each with its own SCSI board. That makes 240 nodes, not
too expensive and very fast.
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