Abstract: A set of like tasks to be performed is organized into a first group. Upon a determined imbalance between dispatch queue depths greater than a predetermined threshold, the set of like tasks is reassigned to an additional group.

Abstract: An apparatus, system, and method are disclosed for relocating storage pool hot spots. An identification module identifies a hot spot on a first storage pool if accesses to the first storage pool exceed an access threshold. The first storage pool is part of a plurality of storage pools. Each storage pool comprises a plurality of logical segments from a plurality of storage devices. Each storage device is of a specified class. A migration module dynamically migrates data of a first logical segment to a second storage pool. The migration is transparent to a host and the data of the first logical segment is continuously available to the host.

Abstract: A processor, operable in a computing storage environment, allocates portions of a Scatter Index Table (SIT) disproportionately between a larger portion dedicated for meta data tracks, and a smaller portion dedicated for user data tracks, and processes a storage operation through the disproportionately allocated portions of the SIT using an allocated number of Task Control Blocks (TCB).

Abstract: For a plurality of input/output (I/O) operations waiting to assemble complete data tracks from data segments, a process, separate from a process responsible for the data assembly into the complete data tracks, is initiated for waking a predetermined number of the waiting I/O operations. A total number of I/O operations to be awoken at each of an iterated instance of the waking is limited.

Abstract: Data operations, requiring a lock, are batched into a set of operations to be performed on a per-core basis. A global lock for the set of operations is periodically acquired, the set of operations is performed, and the global lock is freed so as to avoid excessive duty cycling of lock and unlock operations in the computing storage environment.

Abstract: A processor, operable in a computing storage environment, allocates portions of a Scatter Index Table (SIT) disproportionately between a larger portion dedicated for meta data tracks, and a smaller portion dedicated for user data tracks, and processes a storage operation through the disproportionately allocated portions of the SIT using an allocated number of Task Control Blocks (TCB).

Abstract: For a plurality of input/output (I/O) operations waiting to assemble complete data tracks from data segments, a process, separate from a process responsible for the data assembly into the complete data tracks, is initiated for waking a predetermined number of the waiting I/O operations. A total number of I/O operations to be awoken at each of an iterated instance of the waking is limited.

Abstract: For cache/data management in a computing storage environment, incoming data segments into a Non Volatile Storage (NVS) device of the computing storage environment are validated against a bitmap to determine if the incoming data segments are currently in use. Those of the incoming data segments determined to be currently in use are designated to the computing storage environment to protect data integrity.

Abstract: A set of like tasks to be performed is organized into a first group. Upon a determined imbalance between dispatch queue depths greater than a predetermined threshold, the set of like tasks is reassigned to an additional group.

Abstract: Method, system, and computer program product embodiments for facilitating data transfer from a write cache and NVS via a device adapter to a pool of storage devices by a processor or processors are provided. The processor(s) adaptively varies the destage rate based on the current occupancy of the NVS for a particular storage device and stage activity related to that storage device. The stage activity includes one or more of the storage device stage activity, device adapter stage activity, device adapter utilized bandwidth and the read/write speed of the storage device. These factors are generally associated with read response time in the event of a cache miss and not ordinarily associated with dynamic management of the destage rate. This combination maintains the desired overall occupancy of the NVS while improving response time performance.

Abstract: A method to maintain write operation atomicity where a write operation crosses a data storage medium track boundary. The method supplies a storage controller comprising a host adapter, a processor, and a NVS. The host adapter receives from a host computer a write request and data. The method determines if the write request will cross a data storage medium track boundary. If the write request will cross a data storage medium track boundary, the method indicates to the host adapter that the write request comprises a two-track transfer, and writes the data to the NVS as the data is received. If the host computer fails prior to providing all the data to the storage controller, the method discards the data written to the NVS to ensure write operation atomicity.

Abstract: An apparatus, system, and method are disclosed for relocating logical array hot spots. An organization module organizes a plurality of logical arrays. Each logical array comprises a plurality of logical segments from a plurality of storage devices and configured to store data. An identification module identifies a hot spot on a first logical array if accesses to the first logical array exceed an access threshold. A migration module dynamically migrates a first logical segment from the first logical array to a second logical segment of a second logical array, wherein the migration is transparent to a host and data of the first logical segment is continuously available to the host.

Abstract: A Layer 1 transport network, such as an Optical Transport Network (OTN), transports traffic in Layer 1 data transport units. Traffic received at a node of the transport network is mapped to Layer 1 data transport units according to destination such that each Layer 1 data transport unit carries traffic for a particular destination of the transport network. The Layer 1 transport network can carry a plurality of different traffic types and the node can map the received traffic to Layer 1 data transport units according to destination and traffic type. Identification information can be added to an overhead section associated with the Layer 1 data transport unit to indicate at least one of: traffic type and destination of the traffic carried within the data transport unit.

Abstract: An apparatus, system, and method are disclosed for migrating wear spots in solid-state drives. A count module counts lifetime write cycles for logical units of a plurality of solid-state memories. Each logical unit has a logical address. An identification module identifies a wear spot on a first logical unit of a first solid-state memory if a count for the first logical unit exceeds a cycle threshold. A migration module dynamically migrates data of the first logical unit to a second solid-state memory, wherein the data is continuously available at an original logical address.

Abstract: A method, system, and computer program product for preserving data in a storage subsystem having dual cache and dual nonvolatile storage (NVS) through a failover from a failed cluster to a surviving cluster is provided. A memory preserved indicator is initiated to mark tracks on a cache of the surviving cluster to be preserved, the tracks having an image in an NVS of the failed cluster. A destage operation is performed to destage the marked tracks. Subsequent to a determination that each of the marked tracks have been destaged, the memory preserved indicator is disabled to remove the mark from the tracks. If the surviving cluster reboots previous to each of the marked tracks having been destaged, the cache is verified as a memory preserved cache, the marked tracks are retained for processing while all unmarked tracks are removed, and the marked tracks are processed.

Abstract: Non volatile storage may be employed to temporarily store data which is destaged to data storage drives. The non volatile storage is configured to preserve the data through a power outage. Some data may be preserved, but is not needed, such as the result of a failover to another non volatile storage. This unneeded data is tested to verify the non volatile storage by indicating whether the data survived the power cycle from full power to self refresh mode battery power to full power, without risking the loss of data that is needed.

Abstract: A method, system and computer program product for preserving data in a storage subsystem having dual cache and dual nonvolatile storage (NVS) through a failover from a failed cluster to a surviving cluster, the surviving cluster undergoing a rebooting process, is provided. A memory preserved indicator associated with a cache of the surviving cluster is detected. The memory preserved indicator designates marked tracks having an image in an NVS of the failed cluster to be preserved through the rebooting process. A counter in a data structure of the surviving cache is incremented. If a value of the counter exceeds a predetermined value, a cache memory is initialized, and the marked tracks are removed from the cache to prevent an instance of repetitive reboots caused by a corrupted structure in the cache memory.

Abstract: A method to maintain write operation atomicity where a write operation crosses a data storage medium track boundary. The method supplies a storage controller comprising a host adapter, a processor, and a NVS. The primary host adapter receives from a host computer a write request and data. The method determines if the write request will cross a data storage medium track boundary. If the write request will cross a data storage medium track boundary, the method indicates to the host adapter that the write request comprises a two-track transfer, and writes the data to the primary NVS as the data is received. If the host computer fails prior to providing all the data to the storage controller, the method discards the data written to the NVS to ensure write operation atomicity.

Abstract: An apparatus, system, and method are disclosed for data tracking and, in particular, for facilitating failure management within an electronic data communication system. The apparatus includes a tracking module and an error analysis module. The tracking module stores an adapter identifier in a tracking array. The adapter identifier corresponds to a source adapter from which data is received. The error analysis module determines a source of a data failure in response to recognition of the data failure. The data failure may occur on a host adapter, a device adapter, a communication fabric, a multi-processor, or another communication device. The apparatus, system, and method may be implemented in place of or in addition to hardware-assisted data integrity checking within a data storage system.

Abstract: Provided are a method, system, and program for managing write processes in which a list of destination location identifiers for pending write operations is maintained in an array having an array pointer which identifies the next available entry of the array. In one embodiment, the array includes a stack of variable size. Adding a destination location identifier of a pending write operation increases the size of the stack. Removing a destination location identifier of a completed write operation reduces the size of the stack. A stack index may be incremented as write operation destination location identifiers are added and may be decremented as write operation destination location identifiers are removed from the stack.