Downtime required for changing Group preference Policy in UCS

[PranavGupta9527]

Hi All,

We are having 62XX Fi and 22XX IOM module and we need to change the group linking preference from None to Port Channel. I cannot find any document which says that you can change the preference on fly.

Can some confirm if changing the group linking preference from None to Port Channel will cause any service impact or traffic disruption?

Regards,

Pranav Gupta

[Wes Austin]

Changing the setting will not cause an impact, but the changes will not take effect until you re-acknowledge the IOM on the A and B side. Re-acknowledging the IOMs will cause a brief disruption on the respective sides.

https://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/ucs-manager/GUI-User-Guides/Infrastructure-Mgmt/3-1/b_UCSM_GUI_Infrastructure_Management_Guide_3_1/b_UCSM_GUI_Infrastructure_Management_Guide_3_1_chapter_01.html

[PranavGupta9527]

Hi Wes,

Thank you for the confirmation. I would really appreciate if you can answer the below questions as well as our organisation is making major changes in DC.

1. When you say that you need to re-ackowledge the IOM so can this be done on subordinate IOM first and then primary IOM so that we do have a redundancy available?

2. Also Cisco doc says if you want to add more links from IOM to FI you will have to re-ackowledge the chassis so that the traffic can flow from the new links. Can this be achieved just by re-ackowledging the IOM and not the chassis in the same way as mentioned in the 1st point?

Regards,

Pranav Gupta

[Wes Austin · Accepted solution]

1. Yes. Make sure that all the faults clear out on the UCSM side and the vEth paths re-pin before proceeding to the primary side after re-acking subordinate to maintain redundancy.

2. Yes. In older firmware versions an entire chassis re-ack was required. In later firmware releases, we give you the option to re-ack the IOMs only.