HPE EVA Storage

High B2B Credits from zero - MDS9124 and EVA 4400

 
joe77
Occasional Advisor

High B2B Credits from zero - MDS9124 and EVA 4400

Hi all,
we have a EVA4400 connectet to two c-series mds9124 switches. On all ports where the EVA and our Virtual Connect Fibre Channel Modul is connected, we have a high number of bb credits transition from zero.Are there any known issues or any things to consider ?
Thanks !

FC-Port where EVA is connected:

61477 transmit B2B credit transitions from zero
1147464 receive B2B credit transitions from zero
30 receive B2B credit remaining
7 transmit B2B credit remaining
5 REPLIES 5
Johan Guldmyr
Honored Contributor

Re: High B2B Credits from zero - MDS9124 and EVA 4400

Hey!

What are the ports configured like? (not LD or something like that I hope?)
Do you have an EVA4400 with the embedded SAN switch (that one is brocade).

Are they ports set to 8GB - EVA only does 4GB on the host ports.
joe77
Occasional Advisor

Re: High B2B Credits from zero - MDS9124 and EVA 4400

Hi,

no the ports are not configured for long distance. F-Ports configured for 4 Gb/s.
No embedded Switch. EVA Controllers are directly attached to the c-series switches.
Johan Guldmyr
Honored Contributor

Re: High B2B Credits from zero - MDS9124 and EVA 4400

This is quite interesting :)

What firmware are you running on it?

Would you be able to check the ports for port errors? Maybe there is a port with lots of errors causing problems?

Are you seeing links flapping?
joe77
Occasional Advisor

Re: High B2B Credits from zero - MDS9124 and EVA 4400

Hi,
i have checked all ports on all switches.
There are no Port Errors. Only the high number of bb credits from zero..
Fimrware of the c-series switches is 5.0(4) und EVA is 09534000.
The bb credit transition from zero on the ISL is OK.

0 link failures, 0 sync losses, 0 signal losses
0 transmit B2B credit transitions from zero
0 receive B2B credit transitions from zero
Johan Guldmyr
Honored Contributor

Re: High B2B Credits from zero - MDS9124 and EVA 4400

http://www.cisco.com/en/US/docs/switches/datacenter/mds9000/sw/5_0/release/notes/nxos/mds_nxos_rel_notes_504c.html#wp709740

5.0(4c) has a fix concering BB credits (which as far as I can tell, is the same as B2B). But it doesn't appear to be specifically related.

â ¢CSCti98457

Symptom: The Port Monitor triggers a BB credit not available event before 100 msec, even though the configured value for the event to get trigger is 100 ms.

Workaround: This issue is resolved.

-

I looked in the HP SAN Design Reference Guide for BB (B2B is not in there at all) - and all were about long distance things.

-- I don't know :/ Should be possible to alter the default amount of credits. But if you're not having issues I don't see why. Would be nice to have somebody go through the logs maybe and see what's going on. If you want maybe you can post them here and somebody else can go through them?

The support might be able to help you too :)