I have the following scenario for a 2-server FS system with failover functionality:

• I have a number of Gateways registered at FS1
• I have another number of Gateways registered at FS2
• In case I want to do maintenance on FS1 I would like all external gateways to be registered on FS2 and then shutdown FS1
  
• This is not of a problem if I have only a handful of gateways, but in our case they're about 10.000
  
• The goal is to minimze downtime, when I migrate  e.g. 5000 gateways from FS1 to FS2

• 1st method: The normal way would be to register (via xml-rpc or socket) the new Gateway on FS2 and then deregister it on FS1. FS1 sends an unregister (register with expires=0) to the gateway though (after the register from FS2), so this Gateway unfortunately no longer sends calls to any of the 2 FS.
• 2nd method: The other way is to deregister them first on FS1 and then register them all on FS2. Because deregistering and registering takes time with ~5000 Gateways (+ we have to ensure that the new register has to take place after unregister), this results in a significant downtime.

So my question: Is there any way to suppress deregister messages to the gateway?

Best regards
Peter