On 02/14/2013 11:44 PM, Jeremy Linton wrote:
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On 2/14/2013 4:04 PM, Elliott, Robert (Server Storage) wrote:
Like James notes, LUNs should generally be treated as opaque values.
Maybe another issue to consider is how they are being displayed in
userland.
A device with two luns using one of the alternative lun addressing methods is
going to get some pretty strange looking lun numbers showing up in userspace
if they aren't decoded properly.
No. LUNs with anything other than peripheral addressing do look
weird even nowadays.
Cf IBM DS8000 presents me with LUNs like:
# lsscsi
[0:0:0:49409]wlun IBM 2107900 .107 -
[0:0:0:1085358099]disk IBM 2107900 .107 /dev/sda
where the second maps to LUN 401340b100000000.
Again, the initiator _must not_ attempt to decode the LUN.
To stick with the above example, LUN 400040b100000000 and LUN
40b1000000000000 do refer to the same LUN number, albeit on a
different Level. And it's totally up to the target which physical
LUN these numbers refer to. The initiator has to map these numbers
to different devices; to figure out whether the devices are
identical one would have to look at VPD page 0x83.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
[email protected] +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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