Patent ID: 7721144

Claim:
In a data storage network, a method of maintaining data coherency using two or more array management functions (AMFs) that are able to concurrently access a redundancy group, the redundancy group including a plurality of resources, a first one of the AMFs being operative to receive a request, from a host, to perform a first operation on data stored on a first one of the resources, the method comprising: receiving a message from the first AMF at a second AMF sharing access to the first resource so as to permit access to the first resource by the first AMF; receiving replication and state data from the first AMF at the second AMF concurrently with the first AMF beginning to perform the first operation on the data; and upon the first AMF failing to complete the first operation on the data, completing the first operation on the data by the second AMF using the replication and state data from the first AMF.