An apparatus for and method of enhancing reliability within a cluster lock 
processing system having a relatively large number of commodity cluster instruction processors which are managed by a cluster 
lock manager. Because the commodity processors have virtually no 
system viability features such as 
memory protection, failure 
recovery, etc., the cluster / lock processors assume the responsibility for providing these functions. The low cost of the commodity cluster instruction processors makes the 
system almost linearly scalable. The cluster / locking, caching, and 
mass storage accessing functions are fully integrated into a single hardware platform which performs the role of the cluster / lock master. Upon failure of this hardware platform, a second redundant hardware platform converts from slave to master role. The logic for the failure detection and role swapping is placed within 
software, which can run as an application under a commonly available 
operating system. Furthermore, the 
recovery is completely accomplished without assistance of the Host computer(s) or ultimate user(s) coupled via the Host computer(s). Following repair of the failed 
server, it is restarted in an orderly fashion to resume a slave role. For the 
server to be completely restored, coherent memory must be copied from master to slave. Because cluster lock 
processing must be paused throughout the system to transfer the copy, it is important to minimize the transfer time to minimize the 
impact on system 
throughput.