Abstract: Provided are a method, system, and program for reassigning storage volumes from a failed processing system to a surviving processing system. A first processing system detects a failure of a second processing system. The first processing system determines device groups of storage devices managed by the failed second processing system and determines for each determined device group, hosts that connect to storage devices in the device group. The first processing system sends, for each device group, a unit check to each determined host indicating failure of each device group through one storage device in the device group to which the determined host connects. The determined hosts execute instructions to terminate any I/O operations in progress on the storage devices in the device group in response to the unit check indicating failure of one storage device in the device group and issue, a command to one storage device for the device group to end the busy condition.

Abstract: Provided are a method, system, and article of manufacture, wherein a determination is made that a first data array in a plurality of data arrays has to be repaired to replace a failed storage device within the first data array. A storage device is selected from a selected data array of the plurality of data arrays to replace the failed storage device, wherein a data value corresponding to the selected data array is less than the data value corresponding to the first data array.

Abstract: Disclosed is a system and program for task processing and monitoring of configuration and state information. A first server process and a second server process are detected. A first agent process is registered with the first server process. A second agent process is registered with the second server process. When a task is to be executed by the first server process, the task is executed with the first agent process. When the task is to be executed by the second server process, the task is executed with the second agent process.

Abstract: Disclosed is a method, system, and program for task processing and monitoring of configuration and state information. A first server process and a second server process are detected. A first agent process is registered with the first server process. A second agent process is registered with the second server process. When a task is to be executed by the first server process, the task is executed with the first agent process. When the task is to be executed by the second server process, the task is executed with the second agent process.

Abstract: An apparatus, system, and method are disclosed for presenting a storage volume as a virtual volume. An attribute module determines a primary volume physical attribute of a primary volume. A presentation module presents the primary volume physical attribute to a host as a target volume virtual attribute of a target volume. A translation module translates communications between a host and the target volume. In one embodiment, a copy module creates a point-in-time copy of the primary volume on the target volume.

Abstract: Provided are a method, system, and program for initiating and using information used for a host, control unit, and logical device connections receiving a request to create a host port to control unit port connection. In a volume group data structure, a volume group entry is defined having a plurality of pointers for the host port and control unit port pair. At least one device address is added to the volume group that is accessible to the host port and control unit port connection by initializing at least one pointer in the volume group entry to address at least one device data structure. For each of the at least one device addresses, indication is made in the at least one device data structure addressed by the at least one pointer in the volume group entry that the device address is accessible to the host port and control unit port connection.

Abstract: Provided are a method, system, and article of manufacture, wherein a plurality of processing nodes in a storage system are partitioned into a plurality of logical processing units, and wherein the plurality of logical processing units can respond to I/O requests from a host coupled to the storage system. At least two logical processing units are grouped, wherein data in a first storage coupled to a first logical processing unit of the least two logical processing units is mirrored by data in a second storage coupled to the second logical processing unit of the at least two logical processing units. In response to a failure of the first logical processing unit, an I/O request from the host is responded to via the second logical processing unit.

Abstract: Processor(s) operating a random access memory is subject to reboot processing which comprises clearing the random access memory. Registration is provided of a portion of the random access memory, the registration indicating that data stored in the registered portion of the random access memory is to be preserved during the reboot processing. In reboot processing, the processor responds to the registration, preventing data stored in the registered portion from clearing during the reboot processing.

Abstract: Provided are a method, system, and article of manufacture for detecting data integrity. An indicator is written to invalidate a data block that is capable of being stored in a plurality of sectors of a storage device, wherein the indicator is written to the storage device in at least one sector that is not included in the plurality of sectors. A writing of entire contents of the data block to the plurality of sectors of the storage device is initiated, in response to the writing of the indicator. The indicator is updated to validate the data block, in response to a completion of the writing of the entire contents of the data block to the plurality of sectors of the storage device.

Abstract: Disclosed are a method and system for a storage controller to manage the allocation of emulated storage devices to physical storage segments. The space within the emulated devices is identified by a logical address. The storage controller is in communication with at least one host device and at least one physical storage device. A plurality of tables, each having entry spaces to store segment identification or segment table and entry identification, is established in the storage controller. The tables define a tree structure by which a segment to be accessed is identified by mapping a logical address through the tables to a segment identification. The number of tables, the number of pages in each table, and the number of entries in each page are selected to optimize the amount of space in the storage controller required by the tables and to ensure that the segments may be allocated in any proportion among the emulated storage devices, including all of the segments being allocated to a single emulated device.

Abstract: Provided are a method, system, and program for adding a fourth device to a network including a first, second, and third devices, wherein the first and second devices are directly connected to the third device. The fourth device is directly connected to the third device while the first and second devices remain connected to the third device, and wherein the first and second devices continue to have access to the third device while the fourth device is connected to the third device.

Abstract: Disclosed are a method and system for a storage controller to manage the allocation of emulated storage devices to physical storage segments. The space within the emulated devices is identified by a logical address. The storage controller is in communication with at least one host device and at least one physical storage device. A plurality of tables, each having entry spaces to store segment identification or segment table and entry identification, is established in the storage controller. The tables define a tree structure by which a segment to be accessed is identified by mapping a logical address through the tables to a segment identification. The number of tables, the number of pages in each table, and the number of entries in each page are selected to optimize the amount of space in the storage controller required by the tables and to ensure that the segments may be allocated in any proportion among the emulated storage devices, including all of the segments being allocated to a single emulated device.

Abstract: Processor(s) operating a random access memory is subject to reboot processing which comprises clearing the random access memory. Registration is provided of a portion of the random access memory, the registration indicating that data stored in the registered portion of the random access memory is to be preserved during the reboot processing. In reboot processing, the processor responds to the registration, preventing data stored in the registered portion from clearing during the reboot processing.

Abstract: A network domain includes a plurality of agents and a domain server, the domain server operable for automatically transmitting messages to the agents to reset the agents upon the occurrence of a critical event. Upon receipt of a restart command, each agent terminates executing processes and then restarts processes.

Abstract: Missing interrupt handler (MIH) software features for supporting a variable MIH timeout for I/O requests issued by an operating system (OS). The MIH timeout is varied to prevent a false indication of a failure in an I/O device operation, which is indicated if the MIH timeout occurs. By extending the MIH timeout, the I/O device is given more time to complete its operation, and the extension is provided when the device control unit (CU), or the OS, determines an I/O operation cannot complete before the shortest available MIH timeout. The length of a primary MIH timeout period is extended to a secondary MIH timeout period in response to the OS detecting that an I/O request has a long command that requires a long operating time in the I/O device, or a signal from the device's CU indicating that the current operation in the I/O device is taking an excessive time without the device being in any error condition.

Abstract: Missing interrupt handler (MIH) internal software features support a variable MIH timeout for I/O requests issued by an operating system (OS), when the same OS is involved with both an executing I/O request and a waiting I/O request. The OS varies its MIH timeout period without a signal from any I/O entity to prevent a false indication of a potential failure in a current I/O device operation. If a current I/O request has not completed when the OS senses the end of a primary MIH timeout period, started when issuing that request, the OS then scans the I/O program of that I/O request for any contained long-running command. (Most I/O requests complete during their primary MIH timeout period.) If a long command is found, the OS extends the MIH timeout period from the primary MIH timeout period to a long MIH timeout period, The latter gives the I/O device more time to complete its operation before the OS indicates it has a potential I/O error condition.

Abstract: I/O control unit (CU) features for supporting multiple host operating systems (OSs) which use missing interrupt handler (MIH) timeout functions for detecting potential failures of requested I/O device operations. These CU features support multiple host OSs by preventing them from falsely indicating I/O device failures, when in fact the device has not failed but is merely processing one or more other requests for other host Oss.