Moving Switch Stack from tabletop to 2-post rack

[DoctorHouseToo]

Hello Community,

So I inherited four WS-C3850-48P setup as a stack. It’s sitting on a table and the goal is to move it to a two post rack next to it. StackPower cables used are 0.3 meter and data stack cables are 0.5 meter.

Switch#    Role        Mac Address   Priority  Version  State
------------------------------------------------------------
     *1       Active                             15         V05       Ready
     2        Standby                           14         V05       Ready
     3        Member                           13         V05       Ready
     4        Member                             1         V07       Ready

Switches are physically stacked top to bottom with the sequence 4, 1, 2, 3. Patch panels are non-existent so Ethernet cables are directly connected to the switches, imagine spaghetti.

What do you think of my strategy below?
1. Move the switches one at a time to minimize downtime, the business runs 24x7.
2. Connect a Cisco SG500-52 (my only spare) next to the stack to serve as a temporary switch.
3. Move all the Ethernet cables from switch #4 to temporary switch.
4. Move switch #4 to the two post rack.
      a.  Do I just yank the power cables to switch #4 or is there a right way to do it?
      b.  Do I need to unjoin from the stack then join later, won’t this mess up the config of the stack? I should not do this right since it would be like having a switch go down and having to replace it, right?
5. Connect longer StackPower and data cables to the stack on the table.
6. Console into stack, run #show switch to check stack status
7. Move Ethernet cables from temporary switch to switch #4.
8. Repeat process for remaining switches.

Any special steps or precautions when moving switch #1 which has the active role?

Please advise as I am a newbie.

Thanks Cisco Community!

[Reza Sharifi]

Hi,

Let me first mention that you should not do any of this work without a maintenance window, as there is always a chance that something unexpected can go wrong, and you don't want your boss and users yelling at you. So, pick a 2-hour maintenance window when you have the least amount of users in the office. The second thing to do is to save the config and make a good copy of the latest config from the primary switch just in case something happens to the start-up config and you need to reload it again.

Do I just yank the power cables to switch #4 or is there a right way to do it?

Since these switches do not have any on/off switch on their PSUs, you simply have to yank the cable out.

Do I need to unjoin from the stack then join later, won’t this mess up the config of the stack? I should not do this right since it

I recommend you first unjoin the switch, disconnect the stacking cable, and then turn off the switch.

Any special steps or precautions when moving switch #1 which has the active role?

I also think that you need to create a new stack starting with switch-4 being the primary switch. This way you move the switches from the old stack to the new one with the correct priority applied.So, the new stack could look like this:

 *4       Active                             15         V05       Ready
     3       Standby                           14         V05       Ready
     2        Member                           13         V05       Ready
      1        Member                           1         V05       Ready

HTH

[DoctorHouseToo]

Very sorry for the late reply since I had to go read up on Cisco's Managing Switch Stacks in order for me to have a better understanding of what the community is recommending. Steps to move SW#4 first, which is the top most on the physical stack:

<reference: https://www.cisco.com/en/US/docs/switches/lan/catalyst3850/software/release/3.2_0_se/multibook/configuration_guide/b_consolidated_config_guide_3850_chapter_01100101.html#con_1178943>

1. Disconnect StackPower cables.
2. Disconnect power to dual PSUs.
3. Disconnect StackWise cables connected to SW#4, replace those cables with longer StackWise cables, STACK-T1-3M.
4. Disconnect cables connected to switch ports and module ports.
5. Mount SW#4 to rack.
6. Reconnect cables to switch ports and module ports.
7. Reconnect longer StackWise cables.
8. Reconnect power cables to dual PSUs (see question below).
9. Change switch priority (see question below).

Step 8 question: The longest StackPower cable available, CAB-SPWR-150CM, 1.5 meter, is not long enough. Can I go without connecting them till I have the entire stack moved over. I am moving one switch per week so this task will cover a span of 3 weeks. What impact will this have on the stack since I did not find any in the reference above.

Step 9 question: What sequence of CLI commands do I execute to apply the priority you recommended, Reza? Please make corrections as necessary:

1. switch 1 priority 10
2. reload slot 1
3. switch 4 priority 15
4. reload slot 4

or 

1. switch 1 priority 10
2. switch 4 priority 15
3. reload

Note: I did not change switch 1 priority to 1 since that is switch 4's priority.

Thanks,

DoctorHouseToo

[Leo Laohoo]

I agree with @Reza Sharifi and there will be an outage. 

I have a better solution:  All switches share the same config, right? 

1. Change the switch number from 3 to 1 "switch 3 renumber 1".  
2. Remove switch 3 from the stack and relocate to the new rack. 
3. Power it up.  
4. Switch 3 (now called switch 1) already has the config so configure switch 3 to become the stack master:  switch 1 priority 15
5. Remove switch 2 from the stack and relocate to the new stack.
6. Change switch 1 and renumber to switch 3
7. Remove switch 1 from the stack and relocate to the new stack.  
8. Move switch 4 to the new stack. 
9. Change the switch priority accordingly.