Hi all
Big dumb realization I just made (with a nudge from Pat): a LUN of N 
doesn't mean the disk has to be dskN (can see the mapping in 'hwmgr 
-show scsi').  Furthermore when presenting to the second host I can hit 
"Advanced Options" and make it the same LUN.
But (a) when creating the disk, does it first asks me for an "OS Unit 
ID" and then for a "LUN"?  I thought they were the same?  Or is "OS Unit 
ID" the "dskN"?
And (b) if I want to go back and renumber the LUNs of existing disks, 
e.g. the clusetr root, etc., to make them consistent (just to be tidy), 
will I break something?
Thanks
John
-----Original Message-----
From: Speakman, John 
Sent: Monday, February 24, 2003 2:18 PM
To: tru64
Cc: Speakman, John
Subject: EVA volumes have different LUNs on different hosts?
Hi all
We have two new GS80s running TruCluster 5.1A attached to an EVA.  
Disclosure: I am used to HSZs and DU 4.0 and rz... devices so I may be 
missing something obvious.  But I have spent quite a while reading the 
docs!
When I make a virtual disk on an EVA, I can assign it a LUN to the host 
(I think I'm assigning a LUN - the EVA's HSV Element Manager software 
calls it an "OS Unit ID").  I can also present it (i.e., make it 
visible) to a host (just one at create time).  When I do, the end result 
is that it's presented to that host at that LUN.  Very good.
However as soon as the volume is created I want to present it to the 
second host.  I can do this but don't seem to have an option to specify 
the LUN again, which is okay but it seems to assign it a random LUN to 
the other host and not use the LUN number I specified for the first 
host.  You can see this in the "Hosts/LUNs/State" window of the "Virtual 
Disk Active Properties" page - for instance, if at create time I specify 
volume "somevolumename" with an OS Unit ID of 2 and that it should be 
presented to host "host1", then after creation I present it to host 
"host2", I can look at the "Hosts/LUNs/State" and see it as 
"host1/Active_at_2" but "host2/Active_at_5".  Where did the 5 come from?  To 
my mind this is horrible - won't my host 1 see it as "dsk2" but host 2 
see it as "dsk5"?  This is the way the engineer set it up so I am loath 
to tinker but what I would really like is that they appear to each host 
with the same LUN.  Is there something about TruCluster 5.X that means I 
can't do this and makes the way the engineer did it okay?
Thanks
John
John Speakman - Manager, Clinical Research Systems
Division of Biostatistics, Memorial Sloan-Kettering Cancer Center, 307 
East 63rd Street, New York, NY 10021, USA
Phone: 646 735 8187 / Fax: 646 735 0013 / E-mail: 
speakman_at_biost.mskcc.org
Received on Mon Feb 24 2003 - 20:11:41 NZDT