Mirror Persistence vs Connection Mirroring

Hi,

 

 

Connection mirroring is used to ensure that the peer LTM has a corresponding connection table for each mirrored connection that the primary unit has. This allows the peer unit to handle existing connections in the event of a failover. Persistence is a mapping of a client to a particular pool member.

 

 

For long lived connections like RDP, it would be good to use persistence mirroring. As RDP handles TCP connection loss gracefully (the server allows the client to resume their application session from where it was left off after establishing a new TCP connection), I don't think you really need to use connection mirroring on LTM.

 

 

Anyone else have suggestions on this?

 

 

Aaron

Hi hoolio,

 

 

why you don't think connection mirroring on LTM is needed?

If the client to RDP VIP connection drops during an LTM failover, the client will automatically retry the connection. As long as you have persistence mirroring enabled, LTM will send the new TCP connection to the original server. And the server will accept the new connection and connect the client to the same virtual session on the RDP server.

 

 

So I don't think the overhead of mirroring connections between LTM peers is worth it as the application handles a TCP connection drop fairly well. I'm not saying you shouldn't use both persistence and connection mirroring for RDP--just that I don't think connection mirroring is a requirement.

 

 

Aaron

gotcha...makes sense. I will enable persistence mirroring and test.

excuse me

 

 

so when situation/application that connection mirroring is must need?

 

 

thank you

After failover, this will be the behavior: ​ YES (Connection + Persistence) Mirroring: No need to re-establish new connection to VIP Same Server based on persistence table. NO Connection Mirroring + YES Persistence Mirroring: Re-establish connection to VIP Same Server based on persistence table. NO (Connection + Persistence) Mirroring: Re-establish connection to VIP May or May not be the same server.