Adding new VSANs/fabrics to IMM UCS

rudd-gates · ‎05-02-2025

Customer has existing IMM UCS 6454 fabrics in production, with legacy MDS switches. We want to add new MDS switches with new VSANs for a storage and fabric "cutover" process. (No ISLs between the respective old+new MDS switches in each fabric.) When adding the new FC port channel uplinks to the port policy, we will also add SAN pin groups for both the legacy and new port channels (no VSAN trunking in place today, default dynamic pinning in use). My question is: do we immediately need to update the existing SAN connectivity policy to specify the pin group for existing vHBAs on the legacy fabric, or will this FI port policy change be non-disruptive to server profiles with default (no pin group) settings? Second question: if the SAN connectivity policy MUST immediately be updated, will specifying pin groups on existing vHBAs require a server reboot to activate?

Riaan van Niekerk · ‎05-03-2025

We connect our FI-6536 to multiple SAN fabrics and we do not use pinning groups at all. We just

configure the VSAN on the FC port or FC port channel in the Port Policy used by the Domain Profile,
and in the Fibre Channel Network Policy (which contains the VSAN ID) referenced in the vHBA Template (which is referenced in the SAN Connectivity Policy.

rudd-gates · ‎05-03-2025

Thanks for the response, Riaan. We assumed that, as with disjoint L2 VLANs, the SAN pin groups were required for the uplinks once we introduced another SAN fabric (https://www.cisco.com/c/en/us/support/docs/servers-unified-computing/unified-computing-system/220610-create-port-policy-with-pin-groups-for-a.html). I'm glad to hear that VSAN separation can occur with only the FC Network policy applied to the vHBAs. Can I assume that your VSAN Policies (used by the domain profile) are scoped to 'uplink' for each VSAN in the respective fabrics, with trunking disabled?

Riaan van Niekerk · ‎05-07-2025

If I understand it correctly that trunking and port channels are the same thing (but Cisco prefer/use the term port channel) - some of our SAN connectivity is based on individual ports (e.g. your assumption is correct), whereas for others SAN uplinks are associated with a Port Channel and the VSAN is configured on the Port Channel. We have this on UMM and IMM domains. The configuration is logically identical, only the GUI (where to configure what) is different.

rudd-gates · ‎05-07-2025

In Cisco parlance "trunking" refers to passing multiple VLANs/VSANs across an uplink (whether on single links or port channels), whereas some folk refer to link-aggregated ports as trunk ports. In hindsight, it makes sense that non-trunking configurations do NOT require pin groups, since there is no possibility of sending more than one VSAN across an uplink. We will move forward with this model. Thanks again!