Adding 3rd switch to stack

[Gaurav_Madan]

HI All

I have a LIVE network having 2 switches already stacked as follows :

#show stacking
Stack Topology is a Ring
Active Topology is a Ring
Node MAC Address Slot Stack State Role Flags
------------------ ---- ----------- ------- ---
*00:04:96:35:e5:0b 1 Active Master CA-
00:04:96:51:fd:60 2 Active Backup CA-

I need to add a 3rd switch to this stack in a maintenance window

1) I have made sure that version is compatible
2) I have made sure license level is compatible.

Is the following process fine ? Need some confirmation :
***************************************************************
1) Power down new switch and cable it up in the stack.
2) Power the new switch back up.
3) On the existing stack verify the new switch is being seen by the current stack
(The command below will display the new switches MAC and show that stacking is disabled):
show stacking

4) On the existing stack, type the following commands:
a. configure stacking node-address slot 3
b. synchronize stacking node-address
c. enable stacking node-address
d. reboot node-address

Question # 1 : If above steps are true ; does this mean we will not power down the existing switch stack (slot 1 and 2 ) ?
Question # 2 : If above steps are true ; does that mean that existing config (1:1 -> 1:50 and 2:1 ->2:50) will remain intact and we will additionally see
ports number 3:1 ->3:50 ?
Question # 3 : Hence does that mean that we will be able to do everything through console plugged in existing master switch (slot 1 console in my case) ?

Please guide on the steps to be followed as we will have limited time to do this activity

[Chris_H]

it is recommended to have slot 1 stack-port 1 go to slot 2 - stack port 2, then slot 2 - stack-port 1 go to slot 3 - stack-port 2.. this way you can connect slot 3 port 1 back to slot 1 stack-port 2.

it is not necessary to isolate slot 2 as bill already mentioned, just leave one link between slot 1 and slot 2 active and the existing stack will keep on working

[Darren_Saliva]

you should also make sure that the same partition is used.

[Bill_Handler]

If you have a closed loop, and it looks like you do, unplug the stacking cable from stacking port 1 on switch 1 (the other end should go into stacking port 2 on switch 2) and plug that into stacking port 1 on switch 3. At this point you should still have a stacking cable going between switch 1 & 2, so switch 2 will not come out of the stack.

Then you should be able to see switch 3 from the console of switch 1 (manager). When you see it there, you can run the stacking commands for switch 3.

You also should have a stacking cable to connect switch 3 (stacking port 2) to switch 1 (stacking port 1). We usually connect that cable after we have the stack up and running.

[Gaurav_Madan]

Thanks .. my only confusion in this case is :

At start of activity ; I will remove the stack cables in existing slot 1 and slot 2 ( as i need to re-arrange them to accomodate slot 3 as well )

earlier stacking is as follows :
SLOT 1
stack-port1 \ /
\ / stack port 2
SLOT 2

I will re-cable it as follows :

SLOT1 --------
/ |
/ |
SLOT2 |
/ |
/ |
SLOT3-------

As soon as I do this ; my slot 2 will also come out of stack . Now each of these 3 will be independent master in themselves

Hence I will be required to do following by logging in console of switch 1

a. configure stacking node-address slot 2
b. synchronize stacking node-address
c. enable stacking node-address
put priority of 14 for slot 2

a. configure stacking node-address slot 3
b. synchronize stacking node-address
c. enable stacking node-address
put priority of 13 for slot 3

Finally reboot the stack completely.

PLease confirm