CSS Box-box redundancy image upgrade

[kunleyemo]

Hi

Please, what is the best pratice to upgrade CSS image without losing service to serverfarm.(image are stored on flash).

The css are in redundancy mode.

(ip redundancy & redundancy-phy are configured)

(1) If ip redundancy master is configure temporarily on the active CSS,then after upgrading the image on the Backup CSS(to a different image),

can redundancy force-master be use on the upgraded CSS to force is to be the master.

So that upgrade can be carried on the other CSS.

(2) If the image have been ftp-ed to the two css,

will changing the primary boot on one of the css automatically recognise the correct image in order that the CSS will be in redundancy mode.

or any method that will prevent both CSS becoming master due to different image .

Thanks

[Gilles Dufour]

you will need console access to both CSS to change the primary boot file manually on both of them.

Then, reboot the backup CSS.

Once it is up, configure 'ip redundancy master' so the CSS will become the master.

Once master, reboot the other CSS.

However, there will be traffic lost as the backup CSS is in a down state. The CSS will have to bring up interfaces and start keepalives.

Also, all active connections will be lost because this solution is not stateful.

Finally, I would like to say that I always recommend vip/interface redundancy [unless you are doing fwlb] as with this solution the backup CSS is *alive* [no need to bring up interfaces and start keepalives], it has faster failover, we have better control on redundancy parameters, and it is stateful if combine with ASR.

Regards,

Gilles.