Abstract:
Provided are a computer program product, system, and method for using an attribute of a write request to determine where to cache data in a storage system having multiple caches including non-volatile storage cache in a sequential access storage device. Received modified tracks are cached in the non- volatile storage device integrated with the sequential access storage device in response to determining to cache the modified tracks. A write request having modified tracks is received. A determination is made as to whether an attribute of the received write request satisfies a condition. The received modified tracks for the write request are cached in the non- volatile storage device in response to determining that the determined attribute does not satisfy the condition. A destage request is added to a request queue for the received write request having the determined attribute not satisfying the condition.
Abstract:
A method, system, and computer program product to preserve data integrity in a mirror and copy environment is disclosed herein. In one embodiment, a method may include receiving a write command and data from a host device. The method may further include writing the data to a primary storage device and attaching a primary sequence number associated with the primary storage device to the write command, thereby providing a numbered write command with a command sequence number. The numbered write command may then be transmitted to a secondary storage device. The method may further include comparing the command sequence number to a secondary sequence number associated with the secondary storage device. If the command sequence number matches the secondary sequence number, then the command may be executed. Otherwise, it may be ignored.
Abstract:
Systems, methods and computer program products for providing indirect data addressing at an I/O subsystem of an I/O processing system. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes receiving a control word for an I/O operation. The control word includes an indirect data address for data associated with the I/O operation. The indirect data address includes a starting location of a list of storage addresses that collectively specify the data, the list spans two or more non-contiguous storage locations. Data is gathered responsive to the list. The gathered data is transmitted to a control unit in the I/O processing system.
Abstract:
An computer program product, apparatus, and method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes the host computer system obtaining a transport command word (TCW) for an I/O operation. The TCW specifies a location of one or more I/O commands and a flag. The flag is set to indicate that the location is an indirect address. The host computer system extracts the location of the one or more I/O commands and the flag from the TCW. The host computer system gathers the one or more I/O commands responsive to the location specified by the TCW and the flag, and then forwards the one or more I/O commands to the control unit for execution.
Abstract:
A computer program product, an apparatus, and a method for processing communications between a target and an initiator an input/output processing system are provided. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes: sending a message from the initiator to the target, the message requesting suspension of input/output operations between the initiator and the target for a period of time, the period of time being defined by the message; responsive to the message, suspending input/output operation messages for the period of time; performing a system change comprising at least one of: at least one update, a computer program installation, a recovery, and a change in operating parameters; and initiating new input/output operations after at least one of: expiration of the period of time and initiation of new input/output operations by the initiator.
Abstract:
A computer program product, apparatus and method for processing a variable length device command word (DCW) at a control unit configured for communication with an input/output (I/O) subsystem in an I/O processing system. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes receiving a DCW at the control unit from the I/O subsystem. The DCW specifies one or more I/O operations and includes a command, a control data count, and control data having a varying length specified by the control data count. The control data is extracted in response to the control data count. The command is then executed in response to the extracted control data to perform the specified one or more I/O operations.
Abstract:
Exemplary method, system, and computer program product embodiments for efficient track destage in secondary storage in a more effective manner, are provided. In one embodiment, by way of example only, for temporal bits employed with sequential bits for controlling the timing for destaging the track in a primary storage, the temporal bits and sequential bits are transferred from the primary storage to the secondary storage. The temporal bits are allowed to age on the secondary storage. Additional system and computer program product embodiments are disclosed and provide related advantages.
Abstract:
An computer program product, apparatus, and method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes the host computer system obtaining a transport command word (TCW) for an I/O operation. The TCW specifies a location of one or more I/O commands and a flag. The flag is set to indicate that the location is an indirect address. The host computer system extracts the location of the one or more I/O commands and the flag from the TCW. The host computer system gathers the one or more I/O commands responsive to the location specified by the TCW and the flag, and then forwards the one or more I/O commands to the control unit for execution.
Abstract:
An article of manufacture, apparatus, and a method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The method includes the host computer system obtaining a transport command word (TCW) for an I/O operation having both input and output data. The TCW specifies a location of the output data and a location for storing the input data. The host computer system forwards the I/O operation to the control unit for execution. The host computer system gathers the output data responsive to the location of the output data specified by the TCW, and then forwards the output data to the control unit for use in the execution of the I/O operation. The host computer system receives the input data from the control unit and stores the input data at the location specified by the TCW.
Abstract:
Provided are a method, system, and article of manufacture, wherein a primary storage control unit receives an information unit from a remote host over a fibre channel connection, wherein persistent information unit pacing is implemented over the fibre channel connection. Information is maintained on how many large writes have been received at the primary storage control unit over at least one logical path established over the fibre channel connection between the primary storage control unit and the remote host, wherein a large write is an input/output (I/O) operation for which a number of data information units that are processed exceeds a default value of an information unit pacing credit. The primary storage control unit adjusts an information unit pacing parameter included in a response sent from the primary storage control unit to the remote host, wherein the adjusting is based at least on the information maintained on how many large writes have been received at the primary storage control unit over the at least one logical path.
Abstract translation:提供了一种方法,系统和制品,其中主存储控制单元通过光纤通道连接从远程主机接收信息单元,其中持续信息单元起搏在光纤通道连接上实现。 维持在通过在主存储控制单元和远程主机之间的光纤通道连接上建立的至少一个逻辑路径在主存储控制单元处接收到多少大写入的信息,其中大写是输入/输出( I / O)操作,其中处理的多个数据信息单元超过信息单元起搏信用的默认值。 主存储控制单元将从主存储控制单元发送的响应中包括的信息单元起搏参数调整到远程主机,其中调整至少基于在主存储器上已经接收到多少大写入的信息 所述至少一个逻辑路径上的控制单元。