Renumbering FEX

[graham.allan]

Does anyone know of a method to renumber a FEX without causing service disruption?

Currently I have the following FEX configuration:-

5548# sh fex

  FEX         FEX           FEX                       FEX

Number    Description      State            Model          

------------------------------------------------------------------------

101  fex01                     Online     N2K-C2248TP-1GE  

103  fex03                     Online     N2K-C2248TP-1GE  

105  fex05                     Online     N2K-C2248TP-1GE  

107  fex07                     Online     N2K-C2248TP-1GE  

109  fex09                     Online     N2K-C2248TP-1GE  

111  fex11                     Online     N2K-C2248TP-1GE  

and ideally I want this to change to a sequential numbering scheme:-

5548# sh fex

  FEX         FEX           FEX                       FEX

Number    Description      State            Model          

------------------------------------------------------------------------

101  fex01                     Online     N2K-C2248TP-1GE  

102  fex02                     Online     N2K-C2248TP-1GE  

103  fex03                     Online     N2K-C2248TP-1GE  

104  fex04                     Online     N2K-C2248TP-1GE  

105  fex05                     Online     N2K-C2248TP-1GE  

116  fex06                     Online     N2K-C2248TP-1GE 

Easy enough to:-

1) Preprovisioning the new FEX number

2) Mirror the config

3) Change the FEX association on the FEX downlink ports on the 5548

but I'm certain this will cause a disruption to the connected hosts ports which are in production on the FEX?

Thanks.

[Reza Sharifi]

I think, you are correct.  As soon as you issue no fex 102 for example, it will break the portchannel and that will cause an outage.

I am not sure if this is possible, but how about this:

If you have 2 ports from each 2248 connected to the 5ks presently, take the other 2 ports and build for example portchannel 102 and than delete po 103.  build po 103 delete po 105 build po 104 delete 107 and so on.

Then again, it may be easier to have a short outage window and re-number them.

HTH

[graham.allan]

In the end, we had to take the hit on downtime to the FEX to renumber, however preprovisioning the new FEX config minimised the outage.

Thanks for your help and consideration.

[jkilleda]

Hello Graham,

Renumbering FEX

No , It's not possible to renumber a FEX without causing service disruption ; you require a downtime for it.

[sbhadrav@cisco.com]

Please find below document URL:-
http://www.cisco.com/c/en/us/products/collateral/switches/nexus-5000-series-switches/confi
guration_guide_c07-543563.html

[sbhadrav@cisco.com]

Sometimes it can take a few minutes for the FEX to transit from offline to online.
N5K----FEX

The Fex comes back online within a minute after renumbering:

===before renumbering========
33.03-5548UP# show fex
  FEX         FEX           FEX                       FEX             
Number    Description      State            Model            Serial   
------------------------------------------------------------------------
108        FEX0108                Online      N2K-C2148T-1GE   FOX1337GEYD
148         FEX148                Online     N2K-C2248TP-1GE   SSI143407R2
==========renumbering===========
33.03-5548UP(config-if)# int po148
33.03-5548UP(config-if)# no fex associate 148
33.03-5548UP(config-if)# no fex 148
33.03-5548UP(config)# int po148

33.03-5548UP(config-if)# fex associate 149
33.03-5548UP(config-if)# fex 149

========after renumbering=========
33.03-5548UP(config-fex)# show fex
  FEX         FEX           FEX                       FEX             
Number    Description      State            Model            Serial   
------------------------------------------------------------------------
108        FEX0108                Online      N2K-C2148T-1GE   FOX1337GEYD
149        FEX0149            Registered     N2K-C2248TP-1GE   SSI143407R2

…………………..
33.03-5548UP(config-fex)# show fex
  FEX         FEX           FEX                       FEX             
Number    Description      State            Model            Serial   
------------------------------------------------------------------------
108        FEX0108                Online      N2K-C2148T-1GE   FOX1337GEYD
149        FEX0149                Online     N2K-C2248TP-1GE   SSI143407R2


===dual homed FEX====

One fex goes to both switches running vPC. 
The fex comes back online within minutes as well after applying changes on both sides.

              ===before change ====
33.02-5596UP# show fex
  FEX         FEX           FEX                       FEX             
Number    Description      State            Model            Serial   
------------------------------------------------------------------------
108        FEX0108   AA Version Mismatch      N2K-C2148T-1GE   FOX1337GEYD  -----------àplease ignore this state, we were running different versions on both N5K switches for testing.
132        Eth1/14                Online    N2K-C2232PP-10GE   SSI1350063S

======renumbering on both sides ========
33.02-5596UP(config)# int po108
33.02-5596UP(config-if)# no fex associate
33.02-5596UP(config-if)#
33.02-5596UP(config-if)# no fex 108
33.02-5596UP(config)#
33.02-5596UP(config)#
33.02-5596UP(config)# int po108
33.02-5596UP(config-if)# fex associate 109
33.02-5596UP(config-if)#
33.02-5596UP(config-if)# fex 109


========after change=========
33.02-5596UP(config-if)# show fex
  FEX         FEX           FEX                       FEX             
Number    Description      State            Model            Serial   
------------------------------------------------------------------------
109        FEX0109       Online Sequence      N2K-C2148T-1GE   FOX1337GEYD
132        Eth1/14                Online    N2K-C2232PP-10GE   SSI1350063S
33.02-5596UP(config-if)# show fex
  FEX         FEX           FEX                       FEX             
Number    Description      State            Model            Serial   
------------------------------------------------------------------------
109        FEX0109                Online      N2K-C2148T-1GE   FOX1337GEYD
132        Eth1/14                Online    N2K-C2232PP-10GE   SSI1350063S