07-19-2012 10:31 AM - edited 03-07-2019 07:52 AM
Greetings,
I have a couple questions I'd appreciate a little guidance with.
I've been assigned a task to expand a 3750X switchstack consisting of 2 members (both WS-C3750X-48T-S) by adding an additional member of the same model. The new switch will not be in the same rack as the existing stack, and so longer stackwise cables have been provided to allow the data stack in this configuration. No worries.
My questions revolve around the power situation. Both of the existing members have dual 350W power supplies, and stack-power cables between them. The stack-power mode has been set to power sharing strict, as follows:
swkSANo>sh stack-
Power stack name: Powerstack-1
Stack mode: Power sharing strict
Stack topology: Ring
Switch 1:
Power budget: 223
Low port priority value: 21
High port priority value: 12
Switch priority value: 3
Port 1 status: Connected
Port 2 status: Not connected
Neighbor on port 1: e8b7.4851.6280
Neighbor on port 2: 0000.0000.0000
Switch 2:
Power budget: 223
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Connected
Port 2 status: Not connected
Neighbor on port 1: e8b7.4851.2d80
Neighbor on port 2: 0000.0000.0000
swkSANo>sh env power
SW PID Serial# Status Sys Pwr PoE Pwr Watts
-- ------------------ ---------- --------------- ------- ------- -----
1A C3KX-PWR-350WAC LIT15071C59 OK Good Good 350/0
1B C3KX-PWR-350WAC LIT14500ZXW OK Good Good 350/0
swkSANo-2#sh env power
SW PID Serial# Status Sys Pwr PoE Pwr Watts
-- ------------------ ---------- --------------- ------- ------- -----
2A C3KX-PWR-350WAC LIT15071MKF OK Good Good 350/0
2B C3KX-PWR-350WAC LIT14500ZY5 OK Good Good 350/0
I have 2 queries here.
1 - Since the stack-power group is only 2 members, is it OK that only one stack-power cable is utilized, or should I attach the other cable?
2 - Since there is no PoE, and the power budget is then presumably rather static, would I be better off changing the mode to redundant, or does powersharing accomplish the same thing in my scenario?
Last question is related to the new stack-member. The new member does not have redundant PS, just a single 350W PS. I do not have longer stack-power cables to loop the new member in, so my thought is this:
Take one of the power supplies out of the existing stack and install it in the new stack member. This way, any one of the 5 total PS can fail, and there will be (presumably) no impact to the operation of any member of the the stack. Does my logic hold water here?
Thanks in advance!
B.
07-19-2012 11:21 AM
Hi,
To have full redundancy, you want to connect the second power cable. Have a look at table-9 in this link:
http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6406/white_paper_c11-578931.html
Regarding your second question, I think you should be fine with strict mode. Default is power-sharing.
Power Share "Strict" Mode
HTH
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