Patent ID: 7774785

Claim:
A method, comprising: performing processing operations in a first logical partition in a first processing complex of a server cluster wherein said first logical partition operates using software code at a first version wherein the processing operations in the first logical partition include data input/output tasks directed to a storage system; updating software code in a second logical partition in said first processing complex from said first version to a second version while continuing to perform the processing operations in the first logical partition; a first transferring processing operations from said first logical partition in said first processing complex, to a third logical partition in a second processing complex of said server cluster wherein the transferred processing operations from the first logical partition include data input/output tasks directed to the storage system wherein said first transferring of processing operations includes quiescing said first logical partition to cause a failover of processing operations from said first logical partition in said first processing complex, to said third logical partition in said second processing complex; transferring partition resources from said first logical partition to said second logical partition after quiescing said first logical partition; and performing a failback operation which includes transferring a first portion of the processing operations from said third logical partition in said second processing complex, to said second logical partition in said first processing complex subsequent to said software updating in said second logical partition, wherein said second logical partition operates using software code at said second version.