Which is the better fail over mechanisam

[Alessandro]

Hi,

Both the scenarios are feasible. In the first scenario, you would have multiple clusters, each with two servers in master-slave configuration. This would be handled by a web load balancing appliance properly configured.

On the other hand, you can certainly setup your own fail-over mechanism. Your client will be notified of any disconnection via the proper callbacks (available in all the client SDKs). In that case, you will just set the new host name before trying the reconnection. Obviously, your client will not know the reason of the disconnection. Perhaps it's not a server fault, but just a network issue. So you will probably end up having both the servers serving requests, losing the initial master-slave configuration.

[dimitarn]

Thanks for the reply
Both servers will be serving requests and if one fails the other takes the load until the 1st get up.
I mean that if i use Option 1.A.2 then the sessions created on the LS 1 will not be replicated to LS 2 until LS 1 get down?

[Alessandro]

Option 1.A.2 implies using a Web Load Balancer. In that case, I confirm that the session migration from one server to another will typically happen only when the first server fails.