METHOD, APPARATUS AND PROGRAM STORAGE DEVICE FOR PERFORMING FAULT TOLERANT CODE UPGRADE ON A FAULT TOLERANT SYSTEM BY DETERMINING WHEN FUNCTIONAL CODE REACHES A DESIRED STATE BEFORE RESUMING AN UPGRADE

摘要

A method, apparatus and program storage device for performing fault tolerant code upgrade on a fault tolerant system by determining when functional code reaches a desired state before resuming an upgrade. A concurrent code-load to a plurality of storage controllers of a storage system is initiated. A role transition is detected. The storage system determines when the storage system returns to a desired state. The code-load is resumed when the storage system returns to the desired state.