Abstract: An apparatus and computer program in a distributed cluster storage network comprises storage control nodes to write data to storage on request from a host; a forwarding layer at a first node to forward data to a second node; a buffer controller at each node to allocate buffers for data to be written; and a communication link between the buffer controller and the forwarding layer at each node to communicate a constrained or unconstrained status indicator of the buffer resource to the forwarding layer. A mode selector selects a constrained mode of operation requiring allocation of buffer resource at the second node and communication of the allocation before the first node can allocate buffers and forward data, or an unconstrained mode of operation granting use of a predetermined resource credit provided by the second to the first node and permitting forwarding of a write request with data.

Abstract: An apparatus, method and computer program in a distributed cluster storage network comprises storage control nodes to write data to storage on request from a host; a forwarding layer at a first node to forward data to a second node; a buffer controller at each node to allocate buffers for data to be written; and a communication link between the buffer controller and the forwarding layer at each node to communicate a constrained or unconstrained status indicator of the buffer resource to the forwarding layer. A mode selector selects a constrained mode of operation requiring allocation of buffer resource at the second node and communication of the allocation before the first node can allocate buffers and forward data, or an unconstrained mode of operation granting use of a predetermined resource credit provided by the second to the first node and permitting forwarding of a write request with data.

Abstract: A data storage system comprises a controller, a first lower performance storage medium and a second higher performance storage medium. The controller is connected to the storage mediums and is arranged to control Input/Output (IO) access to the storage mediums. In operation, the controller is arranged to store an image on the first storage medium, initiate a copy function from the first storage medium to the second storage medium, direct all IO access for the image to the second storage medium, and periodically age data from the second storage medium to the first storage medium.

Abstract: Input/output (I/O) I/O target selection is achieved within a data storage system having clustered nodes of initiators, I/O targets, and grouped storage logical units. A state definition component defines access states for each combination of one or more combinations of a node, an I/O target, and a storage logical unit. A profiler component produces an access state profile for each I/O target. A rank criteria compiler compiles rank criteria as a basis for best-fit identification of I/O targets for a logical unit (LU) group. A best-fit identifier is responsive to the profile component and the rank criteria compiler and identifies a ranked best-fit order of I/O targets for an LU group. A target selector selects an I/O target for an LU group from the ranked best-fit order.

Abstract: A computer system for fast format or reproducing data of a computer data storage device includes a computer system executing a reproducing process for reproducing data. A source disk (Ds) data storage device and a target disk (Dt) data storage device have data communication between each other and communicate with the computer system. The Ds data is reproducible to the Dt, and the Ds has blank regions with no data which corresponds to zero. The Ds having data regions and an intermediary flash copy map (D0) is generated by the program having all logical zeros for copying blank regions in the Ds to the Dt. The Ds is disengaged from reproducing after all data regions are copied from the Ds to the Dt. The reproducing of the Ds to the Dt continues after disengaging the Ds from the reproducing process by copying the zeros of the D0 to the Dt.

Abstract: A data storage system comprises a controller, a first lower performance storage medium and a second higher performance storage medium. The controller is connected to the storage mediums and is arranged to control I/O access to the storage mediums. The controller is further arranged to store an image on the first storage medium, initiate a copy function from the first storage medium to the second storage medium, direct all I/O access for the image to the second storage medium, periodically age data from the second storage medium to the first storage medium, create a new empty bitmap for each period, and in response to an I/O access for data in the image, update the latest bitmap to indicate that the data has been accessed and update the previous bitmaps to indicate that the data has not been accessed.

Abstract: A data storage system comprises a controller, a first lower performance storage medium and a second higher performance storage medium. The controller is connected to the storage mediums and is arranged to control I/O access to the storage mediums. The controller is further arranged to store an image on the first storage medium, initiate a copy function from the first storage medium to the second storage medium, direct all I/O access for the image to the second storage medium, periodically age data from the second storage medium to the first storage medium, create a new empty bitmap for each period, and in response to an I/O access for data in the image, update the latest bitmap to indicate that the data has been accessed and update the previous bitmaps to indicate that the data has not been accessed.

Abstract: A method and apparatus for detecting and preemptively ameliorating potential logic unit thrashing in a storage system having multiple I/O requesters is disclosed. In response to detecting that each of two requesters has usable access to both of the active-passive pair of controllers, one of the active-passive pair of controllers is selected to be designated as an active resource controller. In response to detecting that one of the two requesters has usable access to only one of the active-passive pair of controllers, only one of the active-passive pair of controllers is selected to be designated as an active resource controller. In response to detecting that each of the two requesters has usable access only to different ones of the active-passive pair of controllers, one of the active-passive pair of controllers is selected to be designated as an active resource controller.

Abstract: A data storage system comprises a controller, a first lower performance storage medium and a second higher performance storage medium. The controller is connected to the storage mediums and is arranged to control I/O access to the storage mediums. The controller is further arranged to store an image on the first storage medium, initiate a copy function from the first storage medium to the second storage medium, direct all I/O access for the image to the second storage medium, periodically age data from the second storage medium to the first storage medium, create a new empty bitmap for each period, and in response to an I/O access for data in the image, update the latest bitmap to indicate that the data has been accessed and update the previous bitmaps to indicate that the data has not been accessed.

Abstract: A storage control system comprising: one or more I/O processors for receiving requests to write data; a batch controller for selecting one or more write requests to be placed in a first batch; a first server for transmitting the first batch to a second server in a remote copy pair system; one or more I/O handlers for writing the first batch to completion on a data storage medium, in response to receiving permission from the second server; and one or more clients for communicating with the I/O processors and the I/O handlers, wherein the permission is granted when the second server is notified by the I/O handlers that previous write requests have been completed, wherein the first server is responsive to the completion of the first batch.

Abstract: An apparatus, method and computer program in a distributed cluster storage network comprises storage control nodes to write data to storage on request from a host; a forwarding layer at a first node to forward data to a second node; a buffer controller at each node to allocate buffers for data to be written; and a communication link between the buffer controller and the forwarding layer at each node to communicate a constrained or unconstrained status indicator of the buffer resource to the forwarding layer. A mode selector selects a constrained mode of operation requiring allocation of buffer resource at the second node and communication of the allocation before the first node can allocate buffers and forward data, or an unconstrained mode of operation granting use of a predetermined resource credit provided by the second to the first node and permitting forwarding of a write request with data.

Abstract: A data storage system comprises a controller, a first lower performance storage medium and a second higher performance storage medium. The controller is connected to the storage mediums and is arranged to control I/O access to the storage mediums. The controller is further arranged to store an image on the first storage medium, initiate a copy function from the first storage medium to the second storage medium, direct all I/O access for the image to the second storage medium, periodically age data from the second storage medium to the first storage medium, create a new empty bitmap for each period, and in response to an I/O access for data in the image, update the latest bitmap to indicate that the data has been accessed and update the previous bitmaps to indicate that the data has not been accessed.

Abstract: Write requests from host computers are processed in relation to a thin provisioning storage subsystem. A write request is received from a host computer. The write request identifies a first virtual disk that has been previously assigned to the host computer. It is determined whether the first virtual disk has to be allocated additional physical storage locations of the thin provisioning storage subsystem for storing data associated with the write request. In response to determining that the virtual disk has to be allocated additional physical storage locations, the following is performed. First, a quantity of free space remaining unallocated within physical storage locations of the thin provisioning storage subsystem is determined. Second, where the quantity of free space remaining unallocated within the physical storage locations satisfies a policy threshold associated with a second virtual disk, the second virtual disk is write-inhibited. The first and second virtual disks can be different.

Abstract: An apparatus and system are provided for isolating a storage application from a network interface driver. The apparatus includes a definition module, an application interface, a translation module, and a data buffer. The definition module defines a set of storage application functions. The translation module translates each storage application function to one or more network interface driver functions. The data buffer transfers data blocks between the storage application and the network interface driver.

Abstract: A data storage system comprises a controller, a first lower performance storage medium and a second higher performance storage medium. The controller is connected to the storage mediums and is arranged to control Input/Output (IO) access to the storage mediums. In operation, the controller is arranged to store an image on the first storage medium, initiate a copy function from the first storage medium to the second storage medium, direct all IO access for the image to the second storage medium, and periodically age data from the second storage medium to the first storage medium.

Abstract: Various embodiments for operating a distributed cluster storage network having a host computer system and a storage subsystem are provided. In one embodiment, by way of example only, at a first of a plurality of storage control nodes a request is received to write data to storage from the host computer system. The data is forwarded by a forwarding layer at the first of the plurality of storage control nodes to a second of the plurality of storage control nodes. Buffer resource are allocated for the data to be written to the storage by a buffer control component at each of the plurality of storage control nodes. The constrained status indicator of the buffer resource is communicated to the forwarding layer. Additional system and computer program product embodiments are disclosed and provide related advantages.

Abstract: A mechanism is provided for managing operations in a data storage system. A first storage controller monitors operation state information associated with a plurality of operation states stored in a data structure. The first storage controller detects a change in the operation state information. The change in the operation state information is in response to a managing entity updating the operation state information to a first operation state in the plurality of operation states in the data structure. Responsive to detecting the change in the operation state information, the first storage controller identifies a reference to a first operation associated with the first operation state updated by the managing entity. The first operation is one operation in a plurality of operations. The first storage controller performs the first operation associated with the first operation state.

Abstract: This invention relates to an asynchronous remote copying (ARC) system adapted to operate as a remote copy pair by communicating between primary storage and remote storage of a remote copy pair. The system comprises a primary controller for receiving a write command and writing data to primary storage; a remote controller for receiving a write command and writing data to remote storage; an ARC controller for suppressing the release of the write command to the remote controller if a delay between receiving the write command and the time when the remote storage may accept the data is more than a threshold delay, and the primary controller suppresses recording the data in primary storage until release of the write command to the remote storage.

Abstract: A storage control apparatus, in communication with a cluster of storage devices in a storage network having plural administrator systems, comprises a cluster lock requester component, a cluster lock receiver component and a configuration component, wherein, responsive to receipt of a cluster lock by said cluster lock receiver component, the configuration component is operable to configure a logical resource object within said cluster. The apparatus may also include a cluster lock granter component operable to grant a cluster lock to the cluster lock receiver component responsive to said cluster lock requester component. A method of operating a storage control apparatus includes method steps corresponding to functional components of an apparatus and may be embodied in computer program codes.

Abstract: An apparatus for providing storage control in a network of storage controllers is disclosed. The apparatus includes an owner storage controller; an I/O performing component, an ownership assignment component, a lock manager and a messaging component. The ownership assignment component assigns ownership of metadata for data to an owner storage controller. The lock manager controls the locking of metadata during I/O. The messaging component passes messages among storage controllers to request metadata state, to grant locks, to request release of locks, and to signal lock release. The I/O is performed on data whose metadata is owned by an owner storage controller, subject to compliance with metadata lock protocols controlled by the owner storage controller, and any copy of the data held from time to time is maintained in a coherency relation with the data.