Abstract: Mechanisms for controlling access to storage volumes on the secondary storage system is provided. A determination is made as to whether a first site computing device has sent a notification of a failure condition of a first site. In response to a determination that the notification of the failure condition of the first site has not been received, secondary workloads of a second site computing device are permitted to access storage volumes on the secondary storage system. In response to a determination that the notification of the failure condition of the first site has been received, a mode of operation of the second site is modified from a normal mode of operation to a failure mode of operation. In the failure mode of operation, the storage system controller of the second site blocks at least a portion of access requests from secondary workloads of the second site computing device.

Abstract: In accordance with one aspect of the present description, a node of the distributed computing system has multiple communication paths to a data processing resource lock which controls access to shared resources, for example. In this manner, at least one redundant communication path is provided between a node and a data processing resource lock to facilitate reliable transmission of data processing resource lock signals between the node and the data processing resource lock. Other features and aspects may be realized, depending upon the particular application.

Abstract: In accordance with one aspect of the present description, a node of the distributed computing system has multiple communication paths to a data processing resource lock which controls access to shared resources, for example. In this manner, at least one redundant communication path is provided between a node and a data processing resource lock to facilitate reliable transmission of data processing resource lock signals between the node and the data processing resource lock. Other features and aspects may be realized, depending upon the particular application.

Abstract: Mechanisms are provided for extending cache for an external storage system into individual servers. Certain servers may have cards with cache in the form of dynamic random access memory (DRAM) and non-volatile storage, such as flash memory or solid-state drives (SSDs), which may be viewed as actual extensions of the external storage system. In this way, the storage system is distributed across the storage area network (SAN) into various servers. Several new semantics are used in communication between the cards and the storage system to keep the read caches coherent.

Abstract: Mechanisms are provided for extending cache for an external storage system into individual servers. Certain servers may have cards with cache in the form of dynamic random access memory (DRAM) and non-volatile storage, such as flash memory or solid-state drives (SSDs), which may be viewed as actual extensions of the external storage system. In this way, the storage system is distributed across the storage area network (SAN) into various servers. Several new semantics are used in communication between the cards and the storage system to keep the read caches coherent.

Abstract: Mechanisms for controlling access to storage volumes on the secondary storage system is provided. A determination is made as to whether a first site computing device has sent a notification of a failure condition of a first site. In response to a determination that the notification of the failure condition of the first site has not been received, secondary workloads of a second site computing device are permitted to access storage volumes on the secondary storage system. In response to a determination that the notification of the failure condition of the first site has been received, a mode of operation of the second site is modified from a normal mode of operation to a failure mode of operation. In the failure mode of operation, the storage system controller of the second site blocks at least a portion of access requests from secondary workloads of the second site computing device.

Abstract: Mechanisms for controlling access to storage volumes on the secondary storage system is provided. A determination is made as to whether a first site computing device has sent a notification of a failure condition of a first site. In response to a determination that the notification of the failure condition of the first site has not been received, secondary workloads of a second site computing device are permitted to access storage volumes on the secondary storage system. In response to a determination that the notification of the failure condition of the first site has been received, a mode of operation of the second site is modified from a normal mode of operation to a failure mode of operation. In the failure mode of operation, the storage system controller of the second site blocks at least a portion of access requests from secondary workloads of the second site computing device.

Abstract: An out-of-band to optical conversion component is provided that uses a transmit disable signal and a receive loss of signal (LOS) signal built into optical small form-factor pluggable transceiver and cable to pass the out-of-band protocol between serial attached. SCSI enclosures. The transmit disable signal, when asserted, turns off the optical output, while the receive LOS signal detects the loss of signal. The out-of-band to optical conversion component sits in line on the serial attached SCSI data traffic and strips off the out-of-band signals from the serial attached SCSI expander so that only data flows over the optical cable. The out-of-band to optical conversion component sends the out-of-band signals to the other enclosure using the transmit disable pin on the small form-factor pluggable transceiver and cable. The other enclosure receives the message on the receive LOS signal and transmit it back onto the serial attached SCSI receive data pair.

Abstract: Mechanisms for controlling access to storage volumes on the secondary storage system is provided. A determination is made as to whether a first site computing device has sent a notification of a failure condition of a first site. In response to a determination that the notification of the failure condition of the first site has not been received, secondary workloads of a second site computing device are permitted to access storage volumes on the secondary storage system. In response to a determination that the notification of the failure condition of the first site has been received, a mode of operation of the second site is modified from a normal mode of operation to a failure mode of operation. In the failure mode of operation, the storage system controller of the second site blocks at least a portion of access requests from secondary workloads of the second site computing device.

Abstract: Mechanisms for controlling access to storage volumes on the secondary storage system is provided. A determination is made as to whether a first site computing device has sent a notification of a failure condition of a first site. In response to a determination that the notification of the failure condition of the first site has not been received, secondary workloads of a second site computing device are permitted to access storage volumes on the secondary storage system. In response to a determination that the notification of the failure condition of the first site has been received, a mode of operation of the second site is modified from a normal mode of operation to a failure mode of operation. In the failure mode of operation, the storage system controller of the second site blocks at least a portion of access requests from secondary workloads of the second site computing device.

Abstract: A storage system in a remote copy configuration includes a redirect mechanism. The redirect mechanism determines whether to redirect read operations to a remote storage system, which is part of the remote copy configuration, based on a power management policy and a redirect policy. The redirect mechanism takes into account response time data, input/output demand, power utilization data, and input/output classes and priorities to determine whether to redirect read access requests to the remote storage system. Redirection of read operations to the remote storage system results in reduced power consumption at the local system.

Abstract: A power system which includes a battery (or string of batteries) as well as a preemptive fuse driver, PFD, system. The PFD protection system reliably protects circuits that could be damaged by long term fault currents. More specifically, the PFD protection system includes a sensor and a controller as well as a controlled switch. The controller includes a PFD control module which allows protection to be tuned specifically to the source and load characteristics.

Abstract: In accordance with one aspect of the present description, a node of the distributed computing system has multiple communication paths to a data processing resource lock which controls access to shared resources, for example. In this manner, at least one redundant communication path is provided between a node and a data processing resource lock to facilitate reliable transmission of data processing resource lock signals between the node and the data processing resource lock. Other features and aspects may be realized, depending upon the particular application.

Abstract: In accordance with one aspect of the present description, a node of the distributed computing system has multiple communication paths to a data processing resource lock which controls access to shared resources, for example. In this manner, at least one redundant communication path is provided between a node and a data processing resource lock to facilitate reliable transmission of data processing resource lock signals between the node and the data processing resource lock. Other features and aspects may be realized, depending upon the particular application.

Abstract: A solid state drive includes a first solid state disc controller (SSDC), a second SSDC and a flash array. The flash array includes a first flash port and a second flash port. The first SSDC is configured to connect to the flash array through the first flash port and the second flash array is configured to connect to the flash array through the second flash port.

Abstract: A mechanism is provided for moving control of storage devices from one adapter pair to another. In a trunked disk array configuration, moving the storage devices from one disk array to another disk array begins by attaching the downstream ports of the two independent disk arrays together. The mechanism redefines one set of the ports as upstream ports and through switch zoning makes a set of devices available to the second disk array adapters. By controlling zoning access and performing discovery one device port at a time, the mechanism transfers access and ownership of the RAID group from one adapter pair to another.

Abstract: Mechanisms for controlling access to storage volumes on the secondary storage system is provided. A determination is made as to whether a first site computing device has sent a notification of a failure condition of a first site. In response to a determination that the notification of the failure condition of the first site has not been received, secondary workloads of a second site computing device are permitted to access storage volumes on the secondary storage system. In response to a determination that the notification of the failure condition of the first site has been received, a mode of operation of the second site is modified from a normal mode of operation to a failure mode of operation. In the failure mode of operation, the storage system controller of the second site blocks at least a portion of access requests from secondary workloads of the second site computing device.

Abstract: Mechanisms for controlling access to storage volumes on the secondary storage system is provided. A determination is made as to whether a first site computing device has sent a notification of a failure condition of a first site. In response to a determination that the notification of the failure condition of the first site has not been received, secondary workloads of a second site computing device are permitted to access storage volumes on the secondary storage system. In response to a determination that the notification of the failure condition of the first site has been received, a mode of operation of the second site is modified from a normal mode of operation to a failure mode of operation. In the failure mode of operation, the storage system controller of the second site blocks at least a portion of access requests from secondary workloads of the second site computing device.

Abstract: A solid state drive includes a first solid state disc controller (SSDC), a second SSDC and a flash array. The flash array includes a first flash port and a second flash port. The first SSDC is configured to connect to the flash array through the first flash port and the second flash array is configured to connect to the flash array through the second flash port.

Abstract: A solid state drive includes a first solid state disc controller (SSDC), a second SSDC and a flash array. The flash array includes a first flash port and a second flash port. The first SSDC is configured to connect to the flash array through the first flash port and the second flash array is configured to connect to the flash array through the second flash port. The first SSDC and the second SSDC are both configured to connect to all memory within the flash array and the first SSDC, second SSDC, and flash array are within a common solid state drive.