Messages in this thread | | | Date | Tue, 30 Oct 2001 08:47:14 -0800 (PST) | From | Matthew Jacob <> | Subject | Re: iSCSI support for Linux |
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On Tue, 30 Oct 2001, Ashish A. Palekar wrote:
> Nitin: > > The Target side does support 64 bit LUNs - as recommended by SAM-2. The > SCSI Target Mid-level definition for a LUN is a u64. (Note: The SCSI > Target Mid-Level is a completely different entity than the SCSI > Initiator Mid-Level). The question that is up in the air is how to use > those 64 bits for a good target representation.
IIRC the top 2 bits of the first byte of the 8 byte lun define the layout- this is what you have to look at on the initiator side when you do a REPORT LUNS command.
> > The other thing is that 64 bit LUNs are __VERY_RARELY__ used in the SCSI > world that I am familiar with. So unless you are in a highly specialized > operation where all 64 bits are important to you, you can get by with 32 > bit LUNs. >
I'm not sure I agree. As we move into more and more virtualization types of enviroments, the full 64 bit WWPN is often used as the 'lun'. So while it is true that it's not important now, I suspect in a couple of years it might be.
> On the Initiator side, the LUN issue also needs to be addressed by the > SCSI Initiator Mid-Level. The person to speak to in this regard would be > Eric Youngdale (eric@andante.org). In fact the LUN issue along with the > scan code are some of things on the SCSI todo list - the scan thing > being especially important if you are doing fibre channel to enable > dynamic target discovery. > > Hope this helps > Ashish > > Nitin Dhingra wrote: > > > > Ashish, > > I have seen your and other codes as well, I see that everybody's > > used lun field as supplied by > > middle layer right. No one is using 64-bit field acc. to SAM-2, but Linux > > Scsi Subsystem doesn't support 64-bit > > field it supports only 32-bit. Have you thought something about it and do > > you have any solution to this? > > > > Kindly cc me as I am no longer in the mailing list. > > > > regards, > > nitin > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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