best practice to repalce stacked switches

[sulaimangd]

Hi,

we are going to replace a switch in stacked configuration of two switches (long story, the switch was secondary and due to unknown issue stack for removes by itself, and Cisco TAC recommended to replace the switch.)

the switch which going to be replaced is now the Master switch.

client is asking for a Document (like method of operation) how to proceed with his activity.

is there such document from Cisco that we can send to client, or reference we can use to create such document.

the best i could find is for Cisco 3750 switch.

Thanks 

Sulaiman

[Mark Malone]

Hi

I don't think there is a specific Cisco doc apart from the install docs for stacks but its pretty straight forward , make sure the new switch has exact same ios before install` it will make it easier

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_52_se/configuration/guide/3750scg/swstack.html

This is from a general forum below it will be the same for any 37xx model

For adding a switch to the stack follow these steps:

Step 1) On the new switch give the global command: switch stack-member-number provision type https://static.vmguru.com/wordpress/wp-content/uploads/2010/03/stackingcisco3750-50x50.jpg 50w">

Type is the type of switch you are adding to the stack.

When adding for example a third Cisco switch to the Cisco stack, use the following command:

switch 3 provision ws3750g-24t

Step 2) Power off the new stack member

Step 3) Connect the new member to the Cisco stack using the stacking cables, 1 loop at a time.

Step 4) Power on the new stack member. The switch will come alive and will receive the Cisco IOS version from the master, when that is completed it will be ready to service network requests.

For removing a member switch from the stack use the following steps:

Step 1) Power off the stack member to be removed.

Step 2) Remove the stackwise cable from the switch.

Step 3) Issue the following command on the stack master: no switch stack-member-number provision type

[sulaimangd]

Hi 

Thanks Mark,

we are not adding new switch to the stack.

the switch which is going to be replaced is currently the Master of the stack.

im going to use those steps for replacing the switch, hopefully they are correct.

1. on the secondary switch, i will change the priority to become master.

# switch $StackmemberNumber priority $NewPriorityValue

in this case we have to give the Priority Value as 10 (as an example)

# switch 2 priority 10

2. Restart the stack.

3. Verify is the Secondary has become Master.

# show switch

if it got changed. then proceed to step 4.

4. Power off the Member to be removed.

5. Remove Stack-wise cables, and add the new switch to the stack.

6. Issue the command

# show switch 

verify the stack member ship.

Am i on the correct track here :)

Thanks

[Mark Malone · Accepted solution]

when you remove the master it should auto select another master without having to restart the stack , then when the replacement switch is added once it has the same ios on it it will sync staright away , if the priority isn't setup it will chose anther way as below , what im getting at is you can do this without dropping or restarting the stack

from the doc

All stack members are eligible to be stack masters. If the stack master becomes unavailable, the remaining stack members elect a new stack master from among themselves. The switch with the highest stack member priority value becomes the new stack master.

Stack Master Election and Re-Election

The stack master is elected or re-elected based on one of these factors and in the order listed:

1. The switch that is currently the stack master.

2. The switch with the highest stack member priority value.

---

Note We recommend assigning the highest priority value to the switch that you prefer to be the stack master. This ensures that the switch is re-elected as stack master if a re-election occurs.

---

3. The switch that is not using the default interface-level configuration.

4. The switch with the higher priority feature set and software image combination. These combinations are listed from highest to lowest priority.

[seanroberts01]

I would like to know, when you replace a cisci switch in a stack with the same IOS, will it cause the rest of the stack to reboot?

Cheers

Sean