changing a subnet mask in production

[michael18]

I have four SVIs in the same HSRP group. I need to increase the size of the subnet by changing from /22 to /21. the SVI IP and gateway wont change, just the mask. Is it safe to do this in production hours or can it cause issues?

[marce1000 · Accepted solution]

  - I think it cause issues , because there 'is also HSRP' ; ref https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/9-x/unicast/configuration/guide/l3_cli_nxos/l3_hsrp.pdf
     >....Guidelines and Limitations for HSRP
     >...
     >For IPv4, the virtual IP address must be in the same subnet as the interface IP address.

     There could be unwanted side effects on  a hot-production environment. If you decide to
     proceed the use the command terminal monitor on the switch to get console messages too.

  M.

[michael18]

Thanks Marce

Ill do it out of hours to be on the safe side.