The present invention describes a new method for implementing highly available data-parallel-operations on a computational grid. This new method provides high availability after a server fails or the grid experiences a partial network failure. The present invention invokes the data parallel operation's method on selected objects stored in partitions within a highly available distributed cache. It thereby takes advantage of the use of highly available data partitions implemented by the distributed cache as a means for reliably tracking the progress of method invocations within a data parallel operation even after a server or network failure occurs. Using the cache's partitions as the basis for tracking enables the present invention's method to restart method invocations and thereby ensure completion of the data-parallel operation. It also uses a completion object within the cache to ensure that completion of the data parallel operation is detected and reported in a highly available manner.