Abstract: Applications that use non-volatile random access memory (NVRAM), such as those that apply file system journal writes and database log writes where write operations apply data sequentially over the NVRAM, map the available capacity of the NVRAM in a virtual address space without compromising performance. The NVRAM is segmented into regions with multiple such regions fitting within a volatile RAM element accessible to the application and the NVRAM. One or more regions are loaded in the volatile RAM and reflected in page tables that reference the regions. The page tables are managed on a host computer executing the application. One region space in the volatile RAM is unused and available for transferred information. Mechanisms are provided for dynamically transferring regions and interfacing with the host computer. As the application sequentially accesses information in the stored regions, older regions are removed and new regions loaded from NVRAM to the volatile RAM.

Abstract: An apparatus comprising a memory and a controller. The memory may be configured to (i) implement a cache and (ii) store meta-data. The cache comprises one or more cache windows. Each of the one or more cache windows comprises a plurality of cache-lines configured to store information. Each of the plurality of cache-lines may be associated with meta-data indicating one or more of a dirty state and an invalid state. The controller may be connected to the memory and configured to detect an input/output (I/O) operation directed to a file system. The controller may perform a read-fill based on a hint value when there is a read miss in the cache. The hint value may be based on the application access pattern. The hint value may be passed to a caching layer with a corresponding I/O.

Abstract: Embodiments herein provide for redundant data storage. One storage system includes first and second host systems each comprising a memory and a persistent storage device. The storage system also includes first and second storage controllers each comprising a memory (e.g., DRAM). The memory of the first storage controller is mapped to the memory of the first host system and the memory of the second storage controller is mapped to the memory of the second host system. The first storage controller is operable to DMA data from the persistent storage device of the first host system to the memory of the first storage controller, and to direct the second storage controller to DMA the data to the persistent storage device of the second host system via the memory of the second storage controller.

Abstract: An apparatus comprising a memory and a controller. The memory may be configured to (i) implement a cache and (ii) store meta-data. The cache comprises one or more cache windows. Each of the one or more cache windows comprises a plurality of cache-lines configured to store information. Each of the cache-lines comprises a plurality of sub-cache lines. Each of the plurality of cache-lines and each of the plurality of sub-cache lines is associated with meta-data indicating one or more of a dirty state and an invalid state. The controller is connected to the memory and configured to (i) recognize sub-cache line boundaries and (ii) process the I/O requests in multiples of a size of said sub-cache lines to minimize cache-fills.

Abstract: A data storage system and methods for managing data to be transferred between a host and a data volume distributed across solid state storage modules are disclosed. A storage controller couples the host to the data volume and manages data transfers to and from the logical volume. The storage controller receives a set of parameters that define how an array of blocks and chunks of buffered data will be distributed across solid state storage modules. The storage controller receives and buffers data to be stored and transfers the same when the capacity of the buffered data will fill a set of arranged stripes in the defined array in a single write operation.

Abstract: Systems and methods maintain cache coherency between storage controllers using input/output virtualization. In one embodiment, a primary storage controller receives write commands over a virtualized interface, stores the write commands in cache memory, tracks a status of the write commands processed from the cache memory, and stores the status in a portion of the cache memory. A backup storage controller includes a backup cache that receives replications of the write commands via direct memory access operations, and stores the replications of the write commands. The primary storage controller makes the status available to a host system. In response to a failure of the primary storage controller, the backup storage synchronizes with the status from the host system, and resumes I/O operations for the logical volume.

Abstract: Embodiments herein provide for redundant data storage. One storage system includes first and second host systems each comprising a memory and a persistent storage device. The storage system also includes first and second storage controllers each comprising a memory (e.g., DRAM). The memory of the first storage controller is mapped to the memory of the first host system and the memory of the second storage controller is mapped to the memory of the second host system. The first storage controller is operable to DMA data from the persistent storage device of the first host system to the memory of the first storage controller, and to direct the second storage controller to DMA the data to the persistent storage device of the second host system via the memory of the second storage controller.

Abstract: Systems and methods maintain cache coherency between storage controllers using input/output virtualization. In one embodiment, a primary storage controller receives write commands over a virtualized interface, stores the write commands in cache memory, tracks a status of the write commands processed from the cache memory, and stores the status in a portion of the cache memory. A backup storage controller includes a backup cache that receives replications of the write commands via direct memory access operations, and stores the replications of the write commands. The primary storage controller makes the status available to a host system. In response to a failure of the primary storage controller, the backup storage synchronizes with the status from the host system, and resumes I/O operations for the logical volume.

Abstract: A system and method for managing cache memory of at least one node of a multiple-node storage cluster. A first cache data and a first cache metadata are stored for data transfers between a respective node and regions of a storage cluster receiving at least a first selected number of data transfer requests. When the node is rebooted, a second (new) cache data is stored to replace the first (old) cache data. The second cache data is compiled utilizing the first cache metadata to identify previously cached regions of the storage cluster receiving at least a second selected number of data transfer requests after the node is rebooted. The second selected number of data transfer requests is less than the first selected number of data transfer requests to enable a rapid build of the second cache data.

Abstract: A RAID controller includes a cache memory in which write cache blocks (WCBs) are protected by a RAID-5 (striping plus parity) scheme while read cache blocks (RCBs) are not protected in such a manner. If a received cache block is an RCB, the RAID controller stores it in the cache memory without storing any corresponding parity information. When a sufficient number of WCBs to constitute a full stripe have been received but not yet stored in the cache memory, the RAID controller computes a corresponding parity block and stores the RCBs and parity block in the cache memory as a single stripe.

Abstract: The disclosure is directed to preserving data consistency in a multiple-node data storage system. According to various embodiments, a write log is maintained including log entries for data transfer requests being served by a respective node of the multiple-node data storage system. Rather than maintaining a full write journal of data and parity associated with each data transfer request, the log entries only need to identify portions of the virtual volume being updated according to the data transfer requests served by each node. When a first node fails, a second node takes over administration of a virtual volume for the failed node. Upon taking over for the first (failed) node, the second node resolves any inconsistencies between data and parity in portions of the virtual volume identified the respective log entries. Accordingly, write holes are prevented without substantially increasing memory usage or system complexity.

Abstract: A data storage system is provided that implements a command-push model that reduces latencies. The host system has access to a nonvolatile memory (NVM) device of the memory controller to allow the host system to push commands into a command queue located in the NVM device. The host system completes each IO without the need for intervention from the memory controller, thereby obviating the need for synchronization, or handshaking, between the host system and the memory controller. For write commands, the memory controller does not need to issue a completion interrupt to the host system upon completion of the command because the host system considers the write command completed at the time that the write command is pushed into the queue of the memory controller. The combination of all of these features results in a large reduction in overall latency.

Abstract: A cache controller having a cache supported by a non-volatile memory element manages metadata operations by defining a mathematical relationship between a cache line in a data store exposed to a host system and a location identifier associated with an instance of the cache line in the non-volatile memory. The cache controller maintains most recently used bit maps identifying data in the cache, as well as a data characteristic bit map identifying data that has changed since it was added to the cache. The cache controller maintains a most recently used bit map to replace the recently map at an appropriate time and a fresh bitmap tracks the most recently used bit map. The cache controller uses a collision bitmap, an imposter index and a quotient to modify cache lines stored in the non-volatile memory element.

Abstract: A method and controller device for sharing computing resources in a virtualized environment having a plurality of virtual machines. The method includes assigning a portion of the computing resources to the plurality of virtual machines. The method also includes leasing by a first virtual machine at least a portion of the assigned computing resources of at least one second virtual machine. The first virtual machine leases computing resources from the at least one second virtual machine when the first virtual machine needs additional computing resources and at least a portion of the assigned computing resources of the at least one second virtual machine are not being used by the at least one second virtual machine.

Abstract: The present invention is directed to a method for providing storage acceleration in a data storage system. In the data storage system described herein, multiple independent controllers may be utilized, such that a first storage controller may be connected to a first storage tier (ex.—a fast tier) which includes a solid-state drive, while a second storage controller may be connected to a second storage tier (ex.—a slower tier) which includes a hard disk drive. The accelerator functionality may be split between the host of the system and the first storage controller of the system (ex.—some of the accelerator functionality may be offloaded to the first storage controller) for promoting improved storage acceleration performance within the system.

Abstract: The present disclosure is directed to a system for dynamically adaptive caching. The system includes a storage device having a physical capacity for storing data received from a host. The system may also include a control module for receiving data from the host and compressing the data to a compressed data size. Alternatively, the data may also be compressed by the storage device. The control module may be configured for determining an amount of available space on the storage device and also determining a reclaimed space, the reclaimed space being according to a difference between the size of the data received from the host and the compressed data size. The system may also include an interface module for presenting a logical capacity to the host. The logical capacity has a variable size and may include at least a portion of the reclaimed space.

Abstract: The invention provides an elastic or flexible SSD cache utilizing a hybrid RAID protocol combining RAID-0 protocol for read data and RAID-5 single parity protocol for write data in the same cache array. Read data may be stored in window sized allocations using RAID-0 protocol to avoid allocating an entire RAID stripe for read cache data. In the same SSD volume, dirty write data is stored in row allocations using RAID-5 protocol to provide single parity for the dirty write data. Read data is typically stored a window from the physical device having the largest number of available windows. Write data is stored in a row including the next available window in each arm, which decouples the window structure of the rows from the stripe configuration of the physical memory devices.

Abstract: Applications that use non-volatile random access memory (NVRAM), such as those that apply file system journal writes and database log writes where write operations apply data sequentially over the NVRAM, map the available capacity of the NVRAM in a virtual address space without compromising performance. The NVRAM is segmented into regions with multiple such regions fitting within a volatile RAM element accessible to the application and the NVRAM. One or more regions are loaded in the volatile RAM and reflected in page tables that reference the regions. The page tables are managed on a host computer executing the application. One region space in the volatile RAM is unused and available for transferred information. Mechanisms are provided for dynamically transferring regions and interfacing with the host computer. As the application sequentially accesses information in the stored regions, older regions are removed and new regions loaded from NVRAM to the volatile RAM.

Abstract: An apparatus comprising a memory and a controller. The memory may be configured to (i) implement a cache and (ii) store meta-data. The cache comprises one or more cache windows. Each of the one or more cache windows comprises a plurality of cache-lines configured to store information. Each of the plurality of cache-lines may be associated with meta-data indicating one or more of a dirty state and an invalid state. The controller may be connected to the memory and configured to detect an input/output (I/O) operation directed to a file system. The controller may perform a read-fill based on a hint value when there is a read miss in the cache. The hint value may be based on the application access pattern. The hint value may be passed to a caching layer with a corresponding I/O.

Abstract: Providing active-active failover capability to non-failover capable direct-attached storage (DAS) servers including connecting a first and a second non-failover capable direct-attached storage (DAS) servers to a shared storage pool via an expander that supports storage zoning, configuring a first storage zone including the first DAS server and a first portion of the shared storage pool, configuring a second storage zone including the second DAS server and a second portion of the shared storage pool, detecting that the second DAS server has failed, zoning out the second portion of the shared storage pool and mapping the second portion of the shared storage pool to the first storage zone.