Abstract: A method, system, and computer program product are described for a machine selecting a selected adapter among two or more adapters that perform a same function. The method includes generating a request, at the machine, for the function, and calculating a time indicator associated with each of the two or more adapters based on a respective adapter queue time factor (QTF) associated with each of the two or more adapters, the adapter QTF associated with each of the two or more adapters being a computed value. The method also includes selecting the selected adapter and submitting one or more requests to the selected adapter of the two or more adapters to perform the function based on a comparison of the time indicator associated with each of the two or more adapters.

Abstract: A method, system, and computer program product are described for a machine selecting a selected adapter among two or more adapters that perform a same function. The method includes generating a request, at the machine, for the function, and calculating a time indicator associated with each of the two or more adapters based on a respective adapter queue time factor (QTF) associated with each of the two or more adapters, the adapter QTF associated with each of the two or more adapters being a computed value. The method also includes selecting the selected adapter and submitting one or more requests to the selected adapter of the two or more adapters to perform the function based on a comparison of the time indicator associated with each of the two or more adapters.

Abstract: Provided is a method for correcting untrusted data and avoiding logical device swapping for at least one logical subsystem of at least one computer system. A processor may monitor a primary storage for one or more errors that indicate untrusted data on the primary storage. An error indicating that a data set on the primary storage is an untrusted data set may be identified. In response to the error being identified, a corresponding uncompromised version of the data set may be read from a secondary storage. The corresponding uncompromised version of the data set may be written over the untrusted data set on the primary storage.

Abstract: Provided is a method for correcting pinned data in a primary storage. A primary storage controller may detect a pinned data set on a primary storage. In response to detecting the pinned data set, the primary storage controller may instruct a secondary storage controller to transmit a copy of the pinned data set to the primary storage controller. The copy of the pinned data set may be stored in a secondary storage that is communicatively coupled to the secondary storage controller. The secondary storage may include a synchronous copy of the primary storage. The primary storage controller may receive the copy of the pinned data set from the secondary storage controller. The primary storage controller may also write the copy of the pinned data set over the pinned data set on the primary storage.

Abstract: A methodology for creating and using information identifying what and how software and/or firmware modules are used in computer systems, called functional exploitation data. The functional exploitation data can be used to identify what modules should be updated and how updates should be implemented. The functional exploitation data can also be used to identify other computer systems as candidates for updates based on similarity to computer systems that have reported problems, and propose implementing similar updates on the candidates. Functional exploitation data can also be used to identify under-utilized modules for enhancements or greater advocacy. The functional exploitation data can be implemented in the form of a concatenated string.

Abstract: A computer program product for optimizing page table manipulations is provided and includes a computer readable storage medium having program instructions that are readable and executable by a processing circuit to cause the processing circuit to create and maintain a translation table with a translation look-aside buffer (TLB) disposed to cache priority translations, update the translation table upon de-registration of a DMA address, allocate entries in the translation table from low to high memory addresses during memory registration, maintain a cursor for identifying where to search for available entries upon performance of a new registration, advance the cursor from entry-to-entry in the translation table and wrap the cursor from an end of the translation table to a beginning of the translation table and issue a synchronous TLB invalidation instruction to invalidate the TLB upon at least one wrapping and an entry being identified and updated.

Abstract: A computer-implemented method includes receiving, by a storage controller from a first system, a fencing command that includes a parameter identifying a scope of an operation performed on a shared volume, utilizing a processor, setting, by the storage controller, a fencing indicator for at least a second system that is connected to the shared volume, utilizing the processor, where the fencing indicator limits access to the shared volume by the second system, sending, by the storage controller, a notification to the second system, utilizing the processor, where the notification includes the parameter and informs the second system that the access to the shared volume is limited, receiving, by the storage controller, an unfencing command from the second system, utilizing the processor, and resetting or removing the fencing indicator for the second system, utilizing the processor.

Abstract: Provided are a computer program product, system, and method for resource allocation in accordance with one embodiment of the present description, in which a resource allocation such as a buffer credit allocation for a port in a storage area network is initialized as a function of a measurement of a length of a communication link for the port of the storage area network. In one embodiment, the length measurement is a function of a minimum command response time of a command issued over the communication link. Other aspects of resource allocation in accordance with the present description are described.

Abstract: Provided are a computer program product, system, and method for managing access requests from a host to tracks in storage. A cursor is set to point to a track in a range of tracks established for sequential accesses. Cache resources are accessed for the cache for tracks in the range of tracks in advance of processing access requests to the range of tracks. Indication is received of a subset of tracks in the range of tracks for subsequent access transactions and a determination is made whether the cursor points to a track in the subset of tracks. The cursor is set to point to a track in the subset of tracks and cache resources are accessed for tracks in the subset of tracks for anticipation of access transactions to tracks in the subset of tracks.

Abstract: Aspects include a computer-implemented method for managing alias devices across logical control units. Aspects include establishing one or more alias management groups associated with a set of one or more logical control units. Aspects also include responsive to one or more changes to the set of network paths of a first logical control unit in the set of logical control units performing a method comprising: marking a first alias management group associated with the first logical control unit as invalid for alias borrowing. Then, performing a first synchronized CPU enablement operation that ensures each of the plurality of CPUs has enabled. Aspects include determining whether a second alias management group exists having a second set of control units that matches the set of paths of the first control unit and associating the first control unit with the second alias management group.

Abstract: A computer program product for optimizing page table manipulations is provided and includes a computer readable storage medium having program instructions that are readable and executable by a processing circuit to cause the processing circuit to create and maintain a translation table with a translation look-aside buffer (TLB) disposed to cache priority translations, update the translation table upon de-registration of a DMA address, allocate entries in the translation table from low to high memory addresses during memory registration, maintain a cursor for identifying where to search for available entries upon performance of a new registration, advance the cursor from entry-to-entry in the translation table and wrap the cursor from an end of the translation table to a beginning of the translation table and issue a synchronous TLB invalidation instruction to invalidate the TLB upon at least one wrapping and an entry being identified and updated.

Abstract: Aspects include providing automatic access control and security for a synchronous input/output (I/O) link. Providing automatic access control and security includes initializing devices of a storage environment over a first link to verify that the devices are available within the storage environment; building a table of identifiers, where each of the identifiers is assigned one of the devices that have been initialized; and verifying a first device attempting to perform synchronous I/O commands across the synchronization I/O link by confirming that an identifier assigned to the first device is within the table of identifiers.

Abstract: Aspects include sending a request to perform a unit of work that includes a synchronous I/O operation. The sending is from an operating system (OS) executing on a server to firmware located on the server. The synchronous I/O request includes a command request block that includes an operation code identifying the synchronous I/O operation and a identifier of a persistent storage control unit (SCU). The OS waits for the synchronous I/O to complete and the unit of work remains active during the waiting. The firmware detects that the synchronous I/O operation has completed. A command response block that includes completion status information about the synchronous I/O operation is received by the OS from the firmware. The unit of work is completed in response to the I/O operation completing.

Abstract: Aspects include providing automatic access control and security for a synchronous input/output (I/O) link. Providing automatic access control and security includes initializing devices of a storage environment over a first link to verify that the devices are available within the storage environment; building a table of identifiers, where each of the identifiers is assigned one of the devices that have been initialized; and verifying a first device attempting to perform synchronous I/O commands across the synchronization I/O link by confirming that an identifier assigned to the first device is within the table of identifiers.

Abstract: A computer-implemented method for determining correct devices to use in a mass volume migration environment includes reading an I/O configuration definition for a plurality of devices in the mass volume migration environment and definition of a second set of the plurality of devices, wherein the plurality of devices comprise a first set of the plurality of devices. The method includes executing a migration and annotating the first set and the second set with status identifiers. The method also includes responsive to completing a migration of a device in the first set to the associated corresponding device in the second set, updating the annotation of the migrated device in the first set and the corresponding device in the second set and swapping the migrated device in the first set with the corresponding device in the second set, and continuing the migration of devices of the first set to the second set.

Abstract: Aspects include sending a request to perform a unit of work that includes a synchronous I/O operation. The sending is from an operating system (OS) executing on a server to firmware located on the server. The synchronous I/O request includes a command request block that includes an operation code identifying the synchronous I/O operation and an identifier of a persistent storage control unit (SCU). The OS waits for the synchronous I/O to complete and the unit of work remains active during the waiting. The firmware detects that the synchronous I/O operation has completed. A command response block that includes completion status information about the synchronous I/O operation is received by the OS from the firmware. The unit of work is completed in response to the I/O operation completing.

Abstract: Provided are a computer program product, system, and method for resource allocation in accordance with one embodiment of the present description, in which a resource allocation such as a buffer credit allocation for a port in a storage area network is initialized as a function of a measurement of a length of a communication link for the port of the storage area network. In one embodiment, the length measurement is a function of a minimum command response time of a command issued over the communication link. Other aspects of resource allocation in accordance with the present description are described.

Abstract: Aspects include sending a request to perform a unit of work that includes a synchronous I/O operation. The sending is from an operating system (OS) executing on a server to firmware located on the server. The synchronous I/O request includes a command request block that includes an operation code identifying the synchronous I/O operation and a identifier of a persistent storage control unit (SCU). The OS waits for the synchronous I/O to complete and the unit of work remains active during the waiting. The firmware detects that the synchronous I/O operation has completed. A command response block that includes completion status information about the synchronous I/O operation is received by the OS from the firmware. The unit of work is completed in response to the I/O operation completing.

Abstract: Aspects include acquiring measurement data of a synchronous input/output (I/O) link between an operating system and a recipient. The acquiring measurement data can include monitoring operating system usage of synchronous I/O commands on the synchronous I/O link and storing the operating system usage in a measurement block as the measurement data. Further, the measurement block is accessible by the operating system to determine that the measurement data is acquired.

Abstract: Aspects include acquiring measurement data of a synchronous input/output (I/O) link between an operating system and a recipient. The acquiring measurement data can include monitoring operating system usage of synchronous I/O commands on the synchronous I/O link and storing the operating system usage in a measurement block as the measurement data. Further, the measurement block is accessible by the operating system to determine that the measurement data is acquired.