Stack of five Catalyst 2960X's - different boot times?

[andrew.butterworth]

I was working on a customer site earlier and they were replacing a stack of 5 Catalyst 3750's (2 * ws-c3750v2-48ps & 3 * ws-c3750-48ts) with a stack of 5 Catalyst 2960X's (2 * ws-c2960x-48lps-l & 3 * ws-c2960x-48ts-l).  These were brand new and ordered direct from Cisco - all the same hardware revision etc (obviously the PoE and non-PoE are different).  There were stacked with the two PoE in positions 1 & 2 and the three non-PoE as 3, 4 & 5.  They are stacked with switch 1 at the top and 5 at the bottom.  The stack cables link switch 1 port 2 to switch 2 port 1, switch 2 port 2 to switch 3 port 1, switch 3 port 2 to switch 4 port 1, switch 4 port 2 to switch 5 port 1 and finally switch 5 port 2 to switch 1 port 1.

On power up switches 1, 2 & 5 all take roughly the same time to boot, however 3 & 4 take at least another 90-seconds or so (I didn't time it but that seems about right).  I rebooted from the CLI (reload) and also from removing the power and the behaviour is the same.  I also upgraded the IOS to the latest 15.2(6)E, however the same boot times are experienced.

I didn't do any more troubleshooting as the stack was working - albeit three booting quicker than the other two.  However it worries me that there is either some issue with the hardware or possibly a stacking issue?

Has anyone seem a similar issue or know why they would behave like this?

Cheers

Andy

[paul driver]

Hello

You don’t mention anything regards configuring a preferred switch as stack master so i guess what you are seeing here is down to a stack master election process between all the switches, as the switches are booted up at the same time they each will think they are the master switch so an election is going to take place between them

So to negate such process suggest you can manually specify a master switch via priority values also if you do need to power down and up a whole stack, do so in a deterministic manner by powering up the master switch first and then the secondary after about 30 seconds then the rest after another 30 seconds, this way the later switch wont even take part in a election and you may find the boot up process quicker then what you are currently experiencing

res
Paul

[andrew.butterworth]

This appears to be before we even get to stack master election.  It seems to be just the speed at which the IOS image is loaded.  I probably should have got two laptops on the consoles of two switches - one with the 'normal' boot speed and one with the longer boot time and compare what happens.

If I'd have had more time I would have done this.

Andy