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Contributor
Posts: 41
Registered: ‎08-31-2009

High rate of Zero BB Credits per seconds on E-Ports

Hi,

We are monitoring some customer's brocades environment.

There are two fabrics:

each fabric contains Brocade5100, connected to Brocade300 using two E-Ports.

On each E-Port I can see a high rate of average Zero BB credits/sec.

 

What is likely can be the cause?

Ports speed are 8gb, and the are not utilized at all.

 

Thanks

Amir

Regular Contributor
Posts: 161
Registered: ‎12-30-2009

Re: High rate of Zero BB Credits per seconds on E-Ports

Can you post a diagram of how the swithes are interconnected and which ports on which switches have the targets (ie storage) attached?

 

Also what do you consider high rate? And how does it compare against the number of frames.

Do you have historic data which you can share. If you don't have data you can clear the statistics and and wait 15 mins or so and post the figures. portstatsshow will show post the # of frames and tx credit zero against all VC's

Frequent Contributor
Posts: 104
Registered: ‎07-27-2009

Re: High rate of Zero BB Credits per seconds on E-Ports

Start looking here : http://erwinvanlonden.net/2012/07/one-rotten-apple-spoils-the-bunch-1/

 

It'll explain what the most likely problem is.

Contributor
Posts: 41
Registered: ‎08-31-2009

Re: High rate of Zero BB Credits per seconds on E-Ports

Hi,

Thanks for your comments, but still didn't understood the cause for this.

There are two issuses, and I see it from both of the switches:

Some ESX server is doing lots Zero BB/sec, comparing to the other ESXs (see attached report).

Also, on the E-Ports I see a high rate comapring to the rest of the ports.

 

It will be great if you can advise what can be the cause.

 

Attached:

1. Fabrics topology

2. Reports shows the ports statistics.

3. statsportsshow for the following port from each brocade:

    a. port 8 (ESX)

    b. ports 27 & 31 (E-Ports)  

 

Thanks

Contributor
Posts: 26
Registered: ‎09-11-2012

Re: High rate of Zero BB Credits per seconds on E-Ports

You may want to check your fillword settings on the ISL links.

 

Several ports are showing er_bad_os. This might indicate a fillword issue.

 

Run portcfgshow | grep Fill

 

Fillword should be 3 for all 8 G ports.

 

Note, changing an ISL links fillword might require special planning and downtime.

Contributor
Posts: 41
Registered: ‎08-31-2009

Re: High rate of Zero BB Credits per seconds on E-Ports

Hi,

If we change the fillword to 3 on one 8gb port, will it reset this port only, or affect more ports ?

Assuming we have two links to the switch, the question is if we can change one port at a time.

 

Thanks

Valued Contributor
Posts: 931
Registered: ‎12-30-2009

Re: High rate of Zero BB Credits per seconds on E-Ports

portcfgfillword works on a per port basis. so one port is affect at a time, mind you if that port is a trunkport the trunk it belongs to is affected as well.

Contributor
Posts: 41
Registered: ‎08-31-2009

Re: High rate of Zero BB Credits per seconds on E-Ports

Thanks, can you please advise how to check if the ports are trunked ?

 

Thanks

Valued Contributor
Posts: 931
Registered: ‎12-30-2009

Re: High rate of Zero BB Credits per seconds on E-Ports

[ Edited ]

trunkshow

 

admin> trunkshow
1: 4-> 4      10:00:00:xx:xx 2 deskew 16 MASTER
     5-> 5     10:00:00:xx:xx 2 deskew 15

2: 25-> 25 10:00:00:xx:xy 30 deskew 15 MASTER

3: 26-> 26 10:00:00:xx:xy 30 deskew 15 MASTER

 

trunk 1 consists out of ISL on port 4 and 5

Contributor
Posts: 41
Registered: ‎08-31-2009

Re: High rate of Zero BB Credits per seconds on E-Ports

Just checked and we have no trunks.

So some more questuions:

1. The fill word should be on any 8gb port ? Only ISL port ?

2. Does it require some configuration on the ISL port on the other switch ?

3. Does the fill word can be realted to the high rate of Zero BB credits ?

4. Other things need to consider before chnaging the fill word ?

 

Thanks !

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