stackwise catalyst 3750

[bilalsheikh77]

Hello, 

I am trying to add the 4th member in an existing cisco 3750 stack and then IOS upgrade

my concern  is no priority is set on either switch.  

all switches in stack ( master, standby, members) are running priority 1. 

when i will do  the restart and do the IOS upgrade. how it will select the same master, standby and members. 

My impression is i need to issue a commands to set priorities prior to reboot after IOS upgrade. 

sprt10048r01#sh switch
Switch/Stack Mac Address : 00e1.6f48.3500
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 00e1.6f48.3500 1 1 Ready
2 Member 1005.ed3e.5a00 1 1 Ready
3 Member fc99.479a.f080 1 1 Ready

Regards,

[marce1000]

 - Review this document : https://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/71925-cat3750-create-switch-stks.html

            Look for sections concerning setting priorities (for instance) and get familiar with related commands.

 M.

[Joseph W. Doherty]

Without priorities, stack will use its default evaluation for selecting the master.  The default evaluation is defined in the 3750's documentation.  I recall an installed "better" IOS feature set gets priority in master selection.  Then, I recall (?) switch's MACs might be used.  Again, default master selection criteria is documented.  If you want to override, that's what the priority setting is used for.

BTW, you can set priorities before IOS upgrade.  They aren't used until the next stack election (which is caused by the "loss" of the current stack master - which a reboot will cause too).

[bilalsheikh77]

That what my concern is . I don't want to  reboot in an uncertain environment. 

I need to  issue the following and then do the IOS upgrade following by a reboot.

Switch(config)#switch 4 provision ws-c3750x-48
Switch(config)#switch 1 priority 15
Switch(config)#switch 2 priority 14
Switch(config)#switch 2 priority 13
Switch(config)#switch 2 priority 12

and then 

Switch(config)#boot system switch all flash:/c3750e-universalk9-mz.150-2.SE8.bin
Switch(config)#exit
Switch(config)#boot system switch all flash:/c3750e-universalk9-mz.150-2.SE8.bin
Switch(config)#exit
Switch#write memory

Switch#reload

should  do the work. 

Regards,

B

[Reza Sharifi]

Also, don't forget to issue the "show boot" command before rebooting to make sure you have the correct IOS version in the boot variable for all the switches.

If you have access to the physical switches, I always like to make the first switch in the rack sw-1 and the one below it sw-2 and the one below sw-3 and so on... and match that with priority. This way if a switch fails, you know physically which switch is that.

something like:

sw-1-ru-20-priority 15 (top switch)

sw-2-ru-19-priority 12

sw-3-ru-18-priority 10

sw-4-ru-17-priority 8

HTH

[Joseph W. Doherty]

Why are you changing switch 2's priority 3 times and boot system twice?

[bilalsheikh77]

Sorry that was typo.

Switch(config)#switch 4 provision ws-c3750x-48
Switch(config)#switch 1 priority 15
Switch(config)#switch 2 priority 14
Switch(config)#switch 3 priority 13
Switch(config)#switch 4 priority 12

and then 

Switch(config)#boot system switch all flash:/c3750e-universalk9-mz.150-2.SE8.bin
Switch(config)#exit
switch#write memory

Switch#reload

[balaji.bandi · Accepted solution]

adding to others' comments - I would advise changing the switch numbering and priority reboot and then upgrade is a wise choice.

since you know the master well and all the commands issued from the master switch.