Wired Intelligent Edge

One of our buildings has an MDF closet with a switch stack containing five 2930M switches. When these were installed, we set one switch with the highest priority and the others with lower priorities, with the understanding that the one with the highest priority would always be the commander. Yesterday we had a power outage in that building and when the switch stack came back online, the switch with the lowest priority had assumed the role of commander.

Mbr
ID Mac Address                Model                                            Pri    Status
--- ----------------- ------------------------------------- --- ---------------
1 8030e0-d43dc0 Aruba JL322A 2930M-48G-PoE+ Switch 255 Standby
2 8030e0-d46fc0 Aruba JL322A 2930M-48G-PoE+ Switch 250 Member
3 8030e0-d3eec0 Aruba JL322A 2930M-48G-PoE+ Switch 245 Member
4 8030e0-d59240 Aruba JL322A 2930M-48G-PoE+ Switch 240 Member
5 8030e0-d562c0 Aruba JL322A 2930M-48G-PoE+ Switch 128 Commander

Everything is working OK, but AirWave says the switch is down because evidently, it's looking for a different switch to be the commander. I'm wondering how it could be that the lowest priority switch became the commander - I thought setting the priorities would avoid that.

Switch no 5 boots up first and become commander and remain as commander. as i know this is the normal behavior to minimize unnecessary reboots.

https://community.arubanetworks.com/t5/Wired-Intelligent-Edge-Campus/How-switch-stack-commander-failover-works/td-p/475264

Technically the VSF member priority determines the possibility of a member device being elected as the Commander and, consequently, the member with assigned higher priority is more likely to be elected as the Commander (but the election process [*] analyzes other parameters as well)...so, to understand what Switch is more likely to become the VSF Commander, it's necessary to exactly understand how the VSF topology changed (e.g. how was the boot sequence, what was the first switch to go online after the power outage...).

Some discussion about the election process was available through this whole thread.

[*] the VSF Commander election occurs each time the VSF topology changes (examples of topology changes are: the VSF is established, the Commander device fails or is removed, the VSF link goes down causing a VSF split, independent VSFs merge, the stack reboots).