Comware

I have 2 buildings connected by a fiber link.   I had one 10GB module in each stack.  Something happenend over the weekend and it looks like either the 10GB module went bad or the SFP is no good.  

What I would like to do it is put 2 10GB modules in both stacks and in case one module fais it fails over to the other (I have 2 fiber lines between the buildings).  Is this possible and what do I need to do to configure this?  If you have a better solution please let me know. 

If you have two Aruba 2920 Stacks (one Stack per site) and you have at least two fiber optic links between your two sites you can setup an aggregated group with two SFP+ interfaces per group, this on each Stack (using, as example, one SFP+ interface on each Stack member...this in case you have two members Stacks...this to enhance resiliency against Stack member failure from the inter-Stack aggregated link standpoint)...the aggregated group (called Trunk in HP/HPE/Aruba jargon) can be configured to use LACP (IEEE 802.3ad) protocol.

Something like trunk 1/25,2/25 trk1 lacp if - as example - you want to aggregate the 25th interface of both Stack members (that command should be applied on each Stack so each end will have its trk1 configured correctly), consider I supposed the 25th interface as an SFP+ interface equipped with a supported Aruba SFP+ Transceiver, YMMV.

Once trk1 (or whatever you call it trkx) is setup on each Stack...then connect fiber optics cables on each end.

Note: with Stack I mean...two or more Aruba 2920 (from 2 up to 4) connected by means of specific Stacking Modules and Cables...that's NOT Management Stacking.

Thanks for the info.  So if I have the following

Building 1      4 HP 2920's Stack (using stacking Module) and I have a 10GB module in say 1/a1 and 3/a1

Building 2      4 HP 2920's Stack (using stacking Module) and I have a 10GB module in say 1/a1 and 3/a1

Building 1 config  trunk 1/a1,3/a1 trk2 lacp

Building 2 config trunk 1/a1,3a1 tkr2 lacp

If 1/a1 went down everything just goes over 3/a1?

Yes, once you will issue those commands:

Aruba 2920 Stack on Site 1:

trunk 1/a1,3/a1 trk2 lacp

Aruba 2920 Stack on Site 2:

trunk 1/a1,3/a1 trk2 lacp

you will obtain a logical interface capable of sustaining two aggregated single 10Gbps physical links managed by LACP...if 1/a1 or 3/a1 will go down traffic will be automatically re-routed to remaining Up port (3/a1 or 1/a1), this on each end.

Clearly if you loose 1/a1 and 3/a1 on the same end...you will lose the entire link.