Changing Chassis/FEX discovery global policy

[Subramanian]

I have 4 Link in Chassis/ FEX discovery global policy.

Link is Port Chassis and Multicast Hash is disabled.

I need to modify this to 2 Link to add more chassis . If I modify the settings , would there be a disturbance ? Can I do one Fabric Interconnect at a time ? if so how .

Can someone please help me .

Thanks in advance.

[Wes Austin]

Just modifying the settings will not cause disruption, but if you plan to remove links between FI and IOM, and the interfaces are not in a port-channel already, you will need to re-pin those vEth interfaces.

If they are already in a port-channel, the vEth will automatically re-pin when you remove interfaces from the port-channel.

You should:

1. Change the preference.

2. Remove Cables/Interfaces that are not being used any longer (move from 4 links to 2 links)

3. Re-ack the IOM individually after you change the cabling.

When you re-ack IOM one at a time, you are taking down the A or B side respectively, so please ensure you have redundancy setup correctly in the operating system if this is a production system.

[Subramanian]

Dear Wes Austin,

Thanks for your help. I am sorry for delayed reply.  At present 4 chassis with 4 links and 1 chassis with 2 links  . All are in production .  Please find below the picture.

As per your suggestion ,

Need to change this to 2 links in the policy.

Remove 2 FCoE cables from each of 4 chassis.

Re-Acknowledge each IOM in each chassis . Subordinate side first and Primary second.

Present Policy

Please let me know if my understanding is correct. Would there be any packet drop. All the chassis have proper redundancy .

I will plan to do this activity during least affected business hours.

Thanks for your kind help.

Thanks,

Subramanian

[Wes Austin]

There will be packet loss, as the port-channel between the FI and IOM will need to be rebuilt when you re-acknowledge the IOM.

If redundancy is setup correctly, you can take down one side at a time (A or B) and not worry about it impacting production.

If you are worried about the potential impacts, test with one host in the chassis shutting down A or B side interfaces and ensure it's failover is working properly. You may also put the hosts in maintenance mode in a particular chassis when you conduct the re-ack procedure.

[Subramanian]

Thanks a lot Wes Austin. I will do it for a chassis over a weekend and update .

Thanks for all your help.

Thanks,

Subramanian