Inconsistent results when upgrading firmware on 5 member MS355 stack

[DennisS]

Our largest stacks have 5 member switches operating in layer-2 mode. The first and last switch members have an uplink to our traditional Catalyst switches e.g.

SWI-1 (uplink discarding)

SWI-2

SWI-3

SWI-4

SWI-5 (uplink forwarding)

• 1st upgrade, scheduled the whole stack to be upgraded at the same time, 2 member switches needed to be power cycled
• 2nd upgrade, I staggered the switch upgrades: 1&2; 3&4 then 5; 1 member switch needed to be power cycled
• 3rd upgrade, I shutdown the discarding uplink connection then staggered the switch upgrades: 1&2; 3&4 then 5; the whole stack needed to be power cycled

The next attempt, I'll stagger each switch individually. Are others finding the same inconsistent results?  This becomes an issue for offices without IT presence.

[cmr]

I had one similar occurrance with a stack of 3 where I scheduled sw3 first and then sw1+sw2.  sw2 needed power cycling.  When I upgraded all 3 together it was fine.

[DennisS]

I upgraded 2 & 3 stacks all together without issue. My hunch is, as the number of member switches increase the greater the likelihood a member switches doesn't recover quick causing other(s) to not come up cleanly.