Remove stack master with no service disruption

[alessandro.corbelli]

Hi,

I have to remove the stack master switch with no service disruption.

I've tried to do this some minutes ago and the whole network was brought down.

Cabling is ok, because before the master power off i've removed all cables connected to it and services was ok, so, the whole routing was on the slave device.

After master poweroff, the slave loss it's connectivity to each device. Should I check something ?

Configuration on the slave is ok, with vlan and trunking properly configured on every interfaces and portchannel was ok and up.

Seems that the whole routing table was non synchronized between members...

[Reza Sharifi · Accepted solution]

Hi,

Is switch priority set correctly on all your switches?

Are you running the same exact IOS on all your switches?

What is the output of "sh switch"?

Did you follow this link to remove the switch?

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00807811ad.shtml#stack6

HTH

[alessandro.corbelli]

Sorry, i've clicked the wrong button.

I haven't followed that instruction, because I would like to simulate a power failure and in that case i'll not be able to follow some steps before the suddenly power failure.

If I power down the master switch, slave will stops to switch packets untile the master comes back.

[Joseph W. Doherty]

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If I remember correctly, loss of stack master will (temporarily) impact L3.  Impact to pure L2 should be minimal although if stack has gateway, gateway's MAC will change unless configured to not so so or using a virtual MAC.  (NB: stack should issue a gratuitous ARP with MAC change.)  Also, if dealing with other network switches and/or routers, you might need to insure this stack and other devices have optimal configuration, e.g. NSF aware or enabled, STP, etc.

[alessandro.corbelli]

There isn't any gateway on stack. I'm using it as plain L2 switches. No IP or similiar at all.

[Reza Sharifi]

If you power down the master, the switch with highest priority should  take over the responsibility of the master and should start forwarding packet with no delays.  That is purpose of stacking.  Check your switches and make sure the priorities are set correctly.

[alessandro.corbelli]

I have only 2 switches, so it can't be a priority issue.

With master down, the only available switch will be the master, regardless it's priority.