Patent ID: 7441144

Claim:
A method, comprising: performing switchover in a redundant computer cluster comprising at least a first computer unit, a second computer unit, and a shared storage unit, wherein said first computer unit and said second computer unit interface said shared storage unit, said shared storage unit comprises at least two data storage resources; executing a first service unit and a second service unit in said first computer unit, both said first service unit and said second service unit comprising at least one software component; maintaining a first file access from said first service unit to a first data storage resource among said at least two data storage resources, said first file access comprising reading and writing data to said first data storage resource; maintaining a second file access from said second service unit to a second data storage resource among said at least two data storage resources, said first file access being independent of said second file access; detecting a switchover condition associated with said first service unit by said first computer unit; releasing said first file access to said first data storage resource by said first computer unit, in response to said switchover condition, while maintaining said second file access; and altering a state of said first service unit in said first computer unit after successful releasing of said first file access to said first data storage resource.