Ray,
You mention number of usable NPIV subchannels are subject to the switch 
limitations.

Are switch limitations what the IBM Redbook is referencing when it says don't 
"use more than 32 subchannels per physical channel in NPIV mode"? 
With the Brocade switch I could use 255 subchannels in NPIV mode?

(see "Introducing N_Port Identifier Virtualization
for IBM System z9"  page 4
http://www.redbooks.ibm.com/redpapers/pdfs/redp4125.pdf )

" Configuration considerations 
Some general recommendations for using NPIV include:
Do not use more than 32 subchannels per physical channel in NPIV mode.
 Also, do not perform more than 128 total target logins (for example, in a 
configuration with 32 subchannels, limit the number of target logins to no more 
than an average of 4). Using more subchannels, target logins, or both can 
create timeouts."



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________________________________________

From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of 
Raymond Higgs
Sent: Saturday, December 08, 2007 2:01 PM
To: [email protected]
Subject: Re: SAN and Linux on zSeries


<snip>
Not all 480 subchannels can be used with NPIV because of switch limitations.  
The 480 number was chosen arbitrarily from the layout of the SIGA vector long 
before NPIV was implemented.  I think Brocade supports the most virtual nports 
per physical port, 255. 

Ray Higgs
System z FCP Development
Bld. 706, B24
2455 South Road
Poughkeepsie, NY 12601
(845) 435-8666,  T/L 295-8666
[EMAIL PROTECTED]

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