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NPIV Client Boot Hanging Fix

IBM Support troubleshoots an NPIV client boot hanging with Error Code 554.

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On Twitter Chris Gibson highlighted an IBM Support document that troubleshoots an NPIV client
boot hanging with Error Code 554
, which I've excerpted below:

"AIX NPIV Client Boot Hanging with Error Code 554 due to max_xfer_size

Cause
This is cause [sic] by client's max_xfer_size setted too high compared to VIOS Fiber Physical Adapter

Environment
AIX & NPIV

Diagnosing The Problem 
To confirm the boot failure is due to max_xfer_size's value too high on AIX Client, perform a Boot Debug on AIX Client.

To enable this Boot Debug follow guidance:
http://www-01.ibm.com/support/docview.wss?uid=isg3T1019037

Then trap the following message: "open of /dev/fscsi0 returned 61"

Resolving The Problem
Boot AIX client partition in Maintenance Mode, put back max_xfer_size value equal or lower to the one configured on the VIOS... .

Then you can set this value in AIX Client ODM (Maintenance Mode) with chdev command and perform a normal Boot.

Another way to address this would be to change "max_xfer_size" on Physical HBA to match Client's one, but this change require VIOS' reboot. This way seems more risky if one of LPARs is not fully operational from Multi-Pathing perspective."

Be sure to read the entire thing.

I love sharing these tips for a couple of reasons. One is self-interest. Many times when I need information on an issue, my web search will return one of my long-forgotten AIXchange posts. And hopefully by raising these issues here maybe you'll think of this post and/or that document, or you'll simply remember to avoid making the max_xfer_size too high in the first place.
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