Reassigning storage volumes from a failed processing system to a surviving processing system

An article of manufacture implementing first code executed by a first processing system in communication with a second processing system and second code executed by hosts in communication with the first and second processing system, wherein the first code and second code are enabled to cause the first processing system and hosts, respectively, to cause operations to be performed, the operations comprising:

• detecting, by a first processing system, a failure of the second processing system;
• determining, by the first processing system, at least one device group of storage devices managed by the failed second processing system;
• determining, by the first processing system, for each determined device group, hosts that connect to storage devices in the device group;
• sending, by the first processing system, for each determined device group, a unit check to each determined host indicating failure of the device group through one storage device in the device group to which the determined host connects;
• executing, by the determined hosts, instructions for each received unit check to terminate any I/O operations in progress on the storage devices in the device group indicated in the received unit check;
• and
• issuing, by the determined hosts, a command to one storage device in each device group for which the unit check was received to end a busy condition for the issuing host.