11-20-2013 02:55 AM
We have two DCX on 8Gbps FOS 7.1.1. Soon we had a performance issue with one of our storages V7000. The issue was in the storage configuration. Anyway, colleagues from IBM investigating the problem made review of the SAN as well and told me that the SAN ports where V7000 is connected should be set with fillword parameter to 3. They mentioned this IBM document:
My question is should I set all 8Gbps ports in these DCXs with fillword to 3, because in Brocade admin guide it is something unclear for me.
Is it a best practice to set fillword to 3 on all 8Ggbps platforms running FOS 6.3.1a and above?
Is it a must?
Or it depends only if there are some problems or specific vendor requirements (as from IBM above)?
I'll appreciate any answers.
11-20-2013 09:18 AM
first of all, please note that this setting only affects 8gb ports running at 8gb speed.
each end device vendor has their own recommendation regarding the fillword settings on the brocade ports connected to their devices. although mode "2" is the formal industry standard (and HDS recommendation), and although many devices will continue to work in the legacy mode "0", most of the vendors recommend using mode "3" because it has a bit more choice and essentially covers modes "1" and "2".
11-20-2013 11:31 PM
Thank you for your response Alexey.
What you have wrote coincide with what I understood from Brocade guides - that it depends on vendor of equipment connected to 8Gb port and should not be set to all 8Gb ports.
Have a nice day,
11-21-2013 02:26 AM
Alexey is completely right, on the other hand, there shouldn't be many vendors that use IDLE at 8G speeds (because at 8G, IDLE as a fillword does not comply with the standar specs anymore).
Being practical, I would configure all the 8G-ports with "portcfgfillword 3" and change it back to 0 if required. But I am pretty sure that very few devices will require that fillword at 8G.
03-23-2014 10:54 AM
03-24-2014 01:39 AM
modifying the fillword resets the port, so the port will go offline/online when the command is executed.
The available fillword values are:
0 | -idle-idle Sets IDLE mode in the Link Init and IDLE as the fill word (default).
1 | -arbff-arbff Sets ARB(ff) in the Link Init and ARB(ff) as the fill word.
2 | -idlef-arbff Sets IDLE mode in the Link Init and ARB(ff) as the fill word.
3 | -aa-then-ia Attempts hardware arbff-arbff (mode 1) first. If the attempt fails to go into active state, this command executes software idle-arb (mode 2). Mode 3 is the preferable to modes 1 and 2 as it captures more cases..
The difference is that '3' tries '1' and then '2'.
03-24-2014 09:29 AM
I did a online change for this. but only had one host and one vm connected via that port. I am wondering how long it takes for that port to reinitialize hen making this change. I want to make the change on all ports live. any suggestions.
03-26-2014 12:09 PM
I've had this run switchwide (all ports), and did not notice any host access issues.
That said, there is a command option to "delay" the port reset (FOS 7 and up, I believe) so that it will take effect at the next PLOGI.
05-19-2014 08:31 PM
You can use the "Passive" CLI parameter with the portcfgfillword command. This way the configuration will just be staged and will become active if the port moves into a non-active state.