Best buffer size for BufferedInput/Output Streams?

Question

I'm developing a client-server application where one server serves an undetermined number of clients. The server spins off threads to service each client individually. The clients send data (serialized objects) to each other via BufferedInput/OutputStreams wrapped in ObjectInput/OutputStreams. The streams are created like this:
toServer = new ObjectOutputStream(new BufferedOutputStream(theSocket.getOutputStream()));
fromServer = new ObjectInputStream(new BufferedInputStream(theSocket.getInputStream()));I've never had more than a handful (5-6) users on the system at one time, and it works fine. However, I haven't the resources to test the system with a large number of clients, and I'm wondering if the default buffer size is enough to handle a potentially large amount of traffic to a client. Should I increase the buffer size just in case, or should I not worry? Does the buffer size even matter when using an ObjectInput/OutputStream?
I'd appreciate any good advice.

Answer 1

There is an underlying buffer size of 1024 in ObjectIn/OutputStream anyway so the buffer should be at least this large. Generally 4k is adequate unless you are doing very high data volumes in which case 16k, 32k, 63k may help. If you are on Windows you should also up the socket send/receive buffers which by default are 8k: change this to at least 28k. The precise value depends on the network link & in theory should be >= the bandwidth-delay product.