HPE EVA Storage

failover of multiple untrunked ISLs

 
johnCatBE
Advisor

failover of multiple untrunked ISLs

I'm wondering about the behaviour of our existing LW ISL's if we want to upgrade GBICS.

In each fabric, we had only a single 2 Gbps LW ISL for each fabric - we decide to improve by adding it another 4 Gbps link.
Presently, both are healthy but no traffic flows across the newer faster 4 Gbps link.

Each link forms its own trunk master.

Our next move is to change the GBICs on the currently used connections from 2 to 4 Gbps.

However as these are the links in use i'm wondering what to expect re. the behaviour of the switches in using the other 4 Gbps ISL ie the one that's presently healthy but not used.

Is this because we're using port based routing? Of course i'm hoping that if i disable the 2 Gbps ISL to replace the GBIC the switch will simply route down the other valid ISL - but i've no way of testing this.

We have two redundant fabrics.

Has anyone been in this situation?
thanks

john
5 REPLIES 5
AWilliams_1
Trusted Contributor

Re: failover of multiple untrunked ISLs

You have to have the same speed links and the ports have to be in the same port group to enable a trunk to form. The two ISLs also have to have the same cable length before the link will form.
johnCatBE
Advisor

Re: failover of multiple untrunked ISLs

Allan

Yes they're both on P29 and P31 on Brocade 4100 switches ie in the same ASIC group.

Traffic is currently on P31 at N2.
P29 is at N4 but nothing is flowing on it.

I have a set of 4 Gbps LW GBICs but it's the behaviour of the switch in switching to the other ISL when the GBICs are replaced that i'm wondering about.

rgds

john
AWilliams_1
Trusted Contributor

Re: failover of multiple untrunked ISLs

How about forcing the 4Gb ports down to 2Gb and see if the trunk forms. If it does you can then replace the SFPs on the old 2Gb ports and then set them all back to 4Gb.
Sheldon Smith
HPE Pro

Re: failover of multiple untrunked ISLs

Not 100% sure, but I thought the ports had to be adjacent, not just in the same ASIC. Can you move one of the lines to P30?

Note: While I am an HPE Employee, all of my comments (whether noted or not), are my own and are not any official representation of the company

Accept or Kudo

johnCatBE
Advisor

Re: failover of multiple untrunked ISLs

Allan

mm..if if did this i'm a little unclear what would happen when i replace the GBICS (from 2 to 4)...the trunk would fail presumably on the replaced line......then i'd need to change the settings on the present 4Gb line to move back from 2Gb.

(hope your following this !!) In other words i'm still risking the loss of the fabric which is what i'm trying to avoid.

Sheldon,

I think they can be in the same 8-port group on the 4100 .....at least we have a valid trunk on P28/P30 at 4Gb SW which appears to support this.

thanks john