Abstract: Embodiments of the present disclosure may relate to methods and a computer program product for allowing writes based on a granularity level. The method for a storage server may include receiving a received granularity level for a particular volume of a storage device of a client computer including an effective duration for the received granularity level. The method may include receiving an anticipated write to the particular volume at an anticipated write granularity level. The method may include verifying whether the anticipated write granularity level substantially matches the received granularity level at the effective duration. The method may also include writing, in response to the anticipated write granularity level substantially matching the received granularity level at the effective duration, the anticipated write to the particular volume for the received granularity level.

Abstract: Embodiments of the present disclosure may relate to methods and a computer program product for allowing writes based on a granularity level. The method for a storage server may include receiving a received granularity level for a particular volume of a storage device of a client computer including an effective duration for the received granularity level. The method may include receiving an anticipated write to the particular volume at an anticipated write granularity level. The method may include verifying whether the anticipated write granularity level substantially matches the received granularity level at the effective duration. The method may also include writing, in response to the anticipated write granularity level substantially matching the received granularity level at the effective duration, the anticipated write to the particular volume for the received granularity level.

Abstract: Provided are a computer program product, system, and method for a computer program product, system, and method for determining an availability score based on available resources of different resource types in a distributed computing environment of storage servers to determine whether to perform a failure operation for one of the storage servers. A health status monitor program deployed in the storage servers performs: maintaining information indicating availability of a plurality of storage server resources for a plurality of resource types; calculating an availability score as a function of a number of available resources of the resource types; and transmitting information on the availability score to a management program. The management program uses the transmitted information to determine whether to migrate services from the storage server from which the availability score is received to at least one of the other storage servers in the distributed computing environment.

Abstract: Provided are a computer program product, system, and method for a computer program product, system, and method for determining an availability score based on available resources of different resource types in a distributed computing environment of storage servers to determine whether to perform a failure operation for one of the storage servers. A health status monitor program deployed in the storage servers performs: maintaining information indicating availability of a plurality of storage server resources for a plurality of resource types; calculating an availability score as a function of a number of available resources of the resource types; and transmitting information on the availability score to a management program. The management program uses the transmitted information to determine whether to migrate services from the storage server from which the availability score is received to at least one of the other storage servers in the distributed computing environment.

Abstract: A method, system and computer-usable medium are disclosed for managing storage control unit input/output (I/0) operations in a multi-host environment. A storage control unit sends a busy status message when it has exhausted its resources to process new I/O requests. Once the utilization of the storage control unit's resources has subsided to a predetermined upper utilization value, it sends an availability status message to a first predetermined number of host systems that are owed an availability status message. After the first predetermined number of availability status messages are sent, the storage control unit then waits for a predetermined period of time before sending a second predetermined number of availability status messages.

Abstract: In one embodiment, a computer program product for managing a reserve command includes a computer readable storage medium having program code embodied therewith, the program code readable and/or executable by a processor to receive, by the processor, a request to access a data set on one or more volumes of at least one direct access storage device (DASD), the request including a reserve command, and each of the one or more volumes including a consecutive set of one or more tracks of the at least one DASD, and reserve one or more extents of the at least one DASD while reserving less than a volume of the at least one DASD and not allowing any other entity than an entity which requested the reserve to access the one or more extents of the at least one DASD that have been reserved.

Abstract: A method for clearing a fault condition at a target device is disclosed herein. In selected embodiments, such a method includes detecting a fault condition at a target device and receiving N instructions before the fault condition is cleared, where the N instructions are unexecutable due to the fault condition. N fault condition indicators are transmitted in response to the N instructions. Clearing of the fault condition is detected when the fault condition no longer exists. Acknowledgments corresponding to the fault condition indicators are received, where each acknowledgment indicates that one of the fault condition indicators has been received. A fault clear indicator is transmitted only after both all N fault condition indicators have been received and clearing of the fault condition has been detected. A corresponding system and computer program product are also disclosed herein.

Abstract: Provided are a computer program product, system, and method for a computer program product, system, and method for determining an availability score based on available resources of different resource types in a distributed computing environment of storage servers to determine whether to perform a failure operation for one of the storage servers. A health status monitor program deployed in the storage servers performs: maintaining information indicating availability of a plurality of storage server resources for a plurality of resource types; calculating an availability score as a function of a number of available resources of the resource types; and transmitting information on the availability score to a management program. The management program uses the transmitted information to determine whether to migrate services from the storage server from which the availability score is received to at least one of the other storage servers in the distributed computing environment.

Abstract: Provided are a computer program product, system, and method for determining an availability score based on available resources of different resource types in a storage system to determine whether to perform a failure operation for the storage system. Information is maintained indicating availability of a plurality of storage system resources for a plurality of resource types. An availability score is calculated as a function of a number of available resources of the resource types. Information on the availability score is transmitted to a failure manager. The failure manager uses the transmitted availability information to determine whether to initiate a storage system failure mode for the storage system.

Abstract: A method for clearing a fault condition at a target device is disclosed herein. In selected embodiments, such a method includes detecting a fault condition at a target device and receiving N instructions before the fault condition is cleared, where the N instructions are unexecutable due to the fault condition. N fault condition indicators are transmitted in response to the N instructions. Clearing of the fault condition is detected when the fault condition no longer exists. Acknowledgments corresponding to the fault condition indicators are received, where each acknowledgment indicates that one of the fault condition indicators has been received. A fault clear indicator is transmitted only after both all N fault condition indicators have been received and clearing of the fault condition has been detected. A corresponding system and computer program product are also disclosed herein.

Abstract: Embodiments of the disclosure relate to setting up a logical path group identification for multiple data storage devices. An aspect of the disclosure concerns a computer implemented method that comprises receiving a host command to establish a group of connection paths between the host and a plurality of storage devices, identifying the group of connection paths, adding each one of the storage devices to the group of connection paths, and reporting to the host those storage devices that could not be successfully added to the group of connection paths. The method maintains host access security to the storage devices by not grouping a device when it is a reset event state.

Abstract: A primary storage controller is configured to communicate with a secondary storage controller via a system data mover. In response to receiving a command to perform a point in time copy of a source volume of the primary storage controller to a target volume of the primary storage controller, a determination is made as to whether the target volume of the primary storage controller is a source for an asynchronous data replication operation, initiated by the system data mover, between the primary storage controller and the secondary storage controller. In response to determining that the target volume of the primary storage controller is the source for the asynchronous data replication operation, initiated by the system data mover, the point in time copy of the source volume of the primary storage controller to the target volume of the primary storage controller is performed.

Abstract: A primary storage controller is configured to communicate with a secondary storage controller via a system data mover. In response to receiving a command to perform a point in time copy of a source volume of the primary storage controller to a target volume of the primary storage controller, a determination is made as to whether the target volume of the primary storage controller is a source for an asynchronous data replication operation, initiated by the system data mover, between the primary storage controller and the secondary storage controller. In response to determining that the target volume of the primary storage controller is the source for the asynchronous data replication operation, initiated by the system data mover, the point in time copy of the source volume of the primary storage controller to the target volume of the primary storage controller is performed.

Abstract: A method, system and computer-usable medium are disclosed for managing storage control unit input/output (I/O) operations in a multi-host environment. A storage control unit sends a busy status message when it has exhausted its resources to process new I/O requests. Once the utilization of the storage control unit's resources has subsided to a predetermined upper utilization value, it sends a availability status message to a first predetermined number of host systems that are owed a availability statue message. After the first predetermined number of availability status messages are sent, the storage control unit then waits for a predetermined period of time before sending a second predetermined number of availability status messages.

Abstract: In one embodiment, a system includes logic adapted for receiving a command from a first system, logic adapted for determining which resources are required to process the command, logic adapted for checking for the required resources before receiving data associated with the command, logic adapted for receiving the data from the first system, logic adapted for checking for the required resources after receiving the data when the checking for the required resources before receiving data indicated that the required resources were not available before receiving the data, logic adapted for sending a status to the first system if the required resources are not available after receiving the data, and logic adapted for processing the command if the required resources are available either before receiving the data or after receiving the data. In more embodiments, a method and computer program product for processing a command are also presented.

Abstract: Embodiments of the disclosure relate to setting up a logical path group identification for multiple data storage devices. An aspect of the disclosure concerns a computer implemented method that comprises receiving a host command to establish a group of connection paths between the host and a plurality of storage devices, identifying the group of connection paths, adding each one of the storage devices to the group of connection paths, and reporting to the host those storage devices that could not be successfully added to the group of connection paths. The method maintains host access security to the storage devices by not grouping a device when it is a reset event state.

Abstract: A primary storage controller is configured to communicate with a secondary storage controller via a system data mover. In response to receiving a command to perform a point in time copy of a source volume of the primary storage controller to a target volume of the primary storage controller, a determination is made as to whether the target volume of the primary storage controller is a source for an asynchronous data replication operation, initiated by the system data mover, between the primary storage controller and the secondary storage controller. In response to determining that the target volume of the primary storage controller is the source for the asynchronous data replication operation, initiated by the system data mover, the point in time copy of the source volume of the primary storage controller to the target volume of the primary storage controller is performed.

Abstract: According to one embodiment, a method includes receiving device information from a source system; building a virtual device on a host system based at least in part on the received device information; at least one of: transferring a reserve of a device stored on a storage device to a target system; and receiving results of transferring the reserve to the target system; determining if the reserve is held by the target system; recording the reserve if the reserve is held by the target system; and sending a notification that the reserve is not held by the target system if the reserve is not held by the target system. Other methods are also described according to various embodiments.

Abstract: In one embodiment, a system includes logic adapted for receiving a command from a first system, logic adapted for determining which resources are required to process the command, logic adapted for checking for the required resources before receiving data associated with the command, logic adapted for receiving the data from the first system, logic adapted for checking for the required resources after receiving the data when the checking for the required resources before receiving data indicated that the required resources were not available before receiving the data, logic adapted for sending a status to the first system if the required resources are not available after receiving the data, and logic adapted for processing the command if the required resources are available either before receiving the data or after receiving the data. In more embodiments, a method and computer program product for processing a command are also presented.

Abstract: A method for clearing a fault condition at a target device is disclosed herein. In selected embodiments, such a method includes detecting a fault condition at a target device and receiving N instructions before the fault condition is cleared, where the N instructions are unexecutable due to the fault condition. N fault condition indicators are transmitted in response to the N instructions. Clearing of the fault condition is detected when the fault condition no longer exists. Acknowledgments corresponding to the fault condition indicators are received, where each acknowledgment indicates that one of the fault condition indicators has been received. A fault clear indicator is transmitted only after both all N fault condition indicators have been received and clearing of the fault condition has been detected. A corresponding system and computer program product are also disclosed herein.