3850 stack issue

[AZKhan]

Hello everyone,

I have connected two 3850 switches in stack and the first one(Switch 1) booted elected as active switch.  I configured priority of switch 1 as 10 so that it may resume its active state in the event of power failure and then back to life. I deliberately disconnected power from switch 1 and switch 2 assumes the active role. Now after powering-up of switch 1, switch 2 still has active role. 

My question is , If i set the priority to 10 (switch 1) then i think it should regains its active state upon resumption of power. 

Another query is, How we manually (forcefully) switchover the active state from one switch to another switch? Any command to manually switch the Active state.?

[Martin L]

Have you changed priority on sw 2 from its default value?  Try 15, max value. On switch 1 set priority as 15 and do test.

Let us know result.

Regards, ML
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[balaji.bandi]

how many switches in the stack :

if 2 switches in the stack - fist switch configured as priority 10 - another switch what priority?

if other switches become master, once the master comes back online it syncs the config from exiting master and stays a member.

until the whole power recycling takes place.

[Seb Rupik · Accepted solution]

Hi there,

The stack election process that occurs during runtime (as opposed to at boot-up) does not have a concept of preemption. Therefore the previous active switch cannot resume its role as the active switch after a reboot even if it has a higher switch priority value. The switch priorty values only come into play when the active switch becomes unavilable and an election takes place.

There is no command to manually select the active switch. You have to cause an election event to cause a new active switch to be selected.

Take a look at this document, in particular:

https://content.cisco.com/chapter.sjs?uri=%2Fsearchable%2Fchapter%2Fcontent%2Fen%2Fus%2Ftd%2Fdocs%2Fswitches%2Flan%2Fcatalyst3850%2Fsoftware%2Frelease%2F16-12%2Fconfiguration_guide%2Fstck_mgr_ha%2Fb_1612_stck_mgr_ha_3850_cg%2Fmanaging_switch_stacks.h...

cheers,

Seb.

[AZKhan]

Thanks.

[Joseph W. Doherty]

"My question is , If i set the priority to 10 (switch 1) then i think it should regains its active state upon resumption of power."

No, for the reason Seb describes.

"Another query is, How we manually (forcefully) switchover the active state from one switch to another switch? Any command to manually switch the Active state.?"

Yes, reload the active switch.  This will cause a new stack election.