When deploying Coherence on IBM JVMs please be aware of the following:
There is an issue with IBM's 1.4.2, and 1.5 JVMs which may prevent them from allocating socket buffers larger then 64K (Note that buffers of 2MB are recommended for Coherence). This issue has been addressed in IBM's 1.4.2 SR7 SDK and 1.5 SR3 SDK. For performance reasons it is suggested that the patch be applied.