If only I could upgrade the server from 2.2. What’s stopping me is an enormous amount of code using the .NET client.
The Cluster can be upgraded independently of the .Net SDK client see the compatibility table in the SDK documentation.
What I have is approximately 200 app servers connecting to an 8 node cluster with 3 buckets. After a huge traffic spike, the connection counts go way up and stay up (approaching the 9000 connection limit) and it looks like the client lib takes it time for releasing the connections. This is making me nervous because I don’t know how to predict the behavior or how to tell the client lib (.NET 1.3.11) to be more aggressive at releasing connections.
In the 1.X .NET SDK, the number of connections is control by minPoolSize and maxPoolSize settings. The defaults are 10 and 20 respectively. The following formula can be used to work out the maximum number of connections:
Number of Buckets * Number of application server * maxPoolSize = total number of connections
In theory the total number of connections in this case could be 12,000 assuming the defaults are being used. This is above the 9,000 I suggest looking at tuning maxPoolSize down. In Couchbase Server 3 the limits have been increase to 30,000.
I believe the 2.X version of the .NET SDK is much more efficient with connection however that will require code changes.