RE: Logical Block address in iSCSI CDB

[Black_David@emc.com]

> My doubt is....  Do the logical block address contained in 
> SCSI CDB inside ISCSI PDUs are actual address of the remote disk.
> Can we change that ????

Yes and no in that order.
 
> What I am trying to do is,.......
> 
>   If SCSI sends only 2 block or 3 blocks, wait and collect data upto 16 
> blocks (Usual max PDU of ISCSI) and send them over the network so that it 
> will reduce the header over-head.

That sort of thing is usually called a proxy.  Proxies can do anything
they want, but have to take full responsibility for the results (e.g.,
if multiple SCSI operations have been combined into a single
iSCSI operation, when the iSCSI response comes back, it has to
be split into the individual responses that SCSI expects to
its individual operations.  iSCSI (like SCSI) generally does
not support scatter-gather over the wire - the blocks in an
individual read or write operation generally have to be contiguous.

Thanks,
--David
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David L. Black, Senior Technologist
EMC Corporation, 42 South St., Hopkinton, MA  01748
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black_david@emc.com       Mobile: +1 (978) 394-7754
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