International Business Machines Corporation

Warren Hawkins

Timothy A Moran

Nicholas Michael O'Rourke

Dominic Tomkins

Christopher Canto

Christopher W Bulmer

A method comprises: installing the target software version on a first node of the storage appliance; restarting the first node of the storage appliance while also running the current software version on other nodes of the storage system; subsequent to said installing the target software version and said restarting of the first node, determining if all hosts of the storage system have discovered paths to volumes on the first node; responsive to determining that all hosts of the storage system have discovered paths to volumes on the first node, permitting the CCU of the nodes to continue to upgrade one of the other nodes of the storage system from the current software version to the target software version; and responsive to determining that not all hosts of the storage system have discovered paths to volumes on the first node, preventing the CCU of the nodes from continuing.

Concurrent code upgrade

Provided are a method, system, and computer program product in which a storage volume is configured to be maintained in a replicated relationship between two storage systems. A reversing is performed of a switch of a direction of replication for a replicated storage volume, in response to determining that host activity does not sufficiently match a pre-switch host activity, where the host activity does not sufficiently match the pre-switch host activity if a predetermined set of criteria is not met.

Switching of replication relationship between storage systems

Communication between target devices using protocol commands being carried out by a target device includes accessing a key for mapping of a plurality of defined patterns of stimuli and defined patterns of resultant protocol commands to a plurality of messages. A defined pattern of stimuli is sent from a target device to an initiator device to prompt a resultant defined pattern of protocol commands to be sent from the initiator device to all target devices that identify as the same device. The protocol commands including Small Computer System Interface (SCSI) specification compliant commands. A selected pattern of protocol command stimuli is sent from a first target device to the initiator device to prompt a resultant pattern of protocol commands from the initiator device to all target devices that identify as the same device thereby communicating the mapped message to other target devices.

Electronic communication between devices using a protocol

A migration replication relationship for data migration between a migration-source volume on a first storage controller and a migration-target volume on a second storage controller, a volume represents a virtualized device. The method presents the migration-source volume and the migration-target volume as a same volume to a host whilst using differentiated target port descriptors to define different discoverable paths to the each. During data migration, the method allows input/output operations to the migration-source volume by presenting target ports of the first storage controller in an available state and deters input/output operations to the migration-target volume by presenting target ports on the second storage controller in a standby state whilst allowing host discovery of paths to the migration-target volume. Once the data migration is complete, the method switches target port states to allow input/output operations to the migration-target volume and to deter input/output operations to the migration-source volume.

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Winchester, United Kingdom

Warren Hawkins