1. A method of performing a two phase commit process for a transaction started by an application program and involving access to one or more resources managed by respective resource managers, wherein it comprises the steps of: enlisting the resource managers participating in the transaction, each executing in a node comprising a central processing unit (CPU), main memory and fixed storage, said enlisting step including associating a priority rank with each identified resource manager based on predefined priority rules; sending a prepare signal to said enlisted resource managers to begin the process of committing the transaction; and if a ready signal is received from all resource managers in response to the prepare signal, committing the resource managers in the order defined from the priority ranks associated with the resource managers.