Can I know what is the maximum connection allowed by Couchbase 2.2 for single memcached bucket? How can I check it and modify it?
Do you mean connection timeout or number of concurrent connections?
Looking at the source code for the .NET SDK v. 2, there does not seem to be an SDK build in MAX value for either (timeout or concurrent) but every connection takes up 16K mem (from the code). But you can set your own Min/max values:
The Couchbase server itself can handle ~10k connections, although this is just a theoretical limit. In general, the fewer connections the better due to resource allocation. The SDK will create up to the MaxSize connections for each node in a cluster, so if you have a 3 node cluster, set the MaxSize to be 10, and have 5 client instances running in a processes, you will be using 3x10x5=150 connections.
Perhaps @pvarley can provide some more depth to maximum number of connections the Couchbase Server can handle?