Abstract: Embodiments serve to balance overall performance of a finite-sized caching system having a first cache of a first cache size and a second cache of a second cache size. A tail portion and a head portion of each of the caches are defined wherein incoming data elements are initially stored in a respective head portion and wherein evicted data elements are evicted from a respective tail portion. Performance metrics are defined wherein a performance metric includes a predicted miss cost that would be incurred when replacing an evicted data elements. A quantitative function is defined to include cache performance metrics and a cache reallocation amount. The cache performance metrics are evaluated periodically to determine a then-current cache reallocation amount. The caches can be balanced by increasing the first cache size by the cache reallocation amount and decreasing the second cache size by the cache reallocation amount.

Abstract: An architecture for implementing a distributed metadata system in a virtualization environment comprising a plurality of servers, wherein each server may access and operate upon the entirety of the metadata in the virtualization environment. In response to a request received at a server to operate upon the metadata, existing metadata associated with the request is read by the server. The server performs one or more updates based upon the retrieved metadata, and attempts to update the corresponding stored metadata. In some embodiments, attempting to update the stored metadata comprises reading the metadata again and comparing it to the originally retrieved metadata, and performing the update only if the newly retrieved metadata matches the originally retrieved metadata.

Abstract: Embodiments serve to balance overall performance of a finite-sized caching system having a first cache of a first cache size and a second cache of a second cache size. A tail portion and a head portion of each of the caches are defined wherein incoming data elements are initially stored in a respective head portion and wherein evicted data elements are evicted from a respective tail portion. Performance metrics are defined wherein a performance metric includes a predicted miss cost that would be incurred when replacing an evicted data elements. A quantitative function is defined to include cache performance metrics and a cache reallocation amount. The cache performance metrics are evaluated periodically to determine a then-current cache reallocation amount. The caches can be balanced by increasing the first cache size by the cache reallocation amount and decreasing the second cache size by the cache reallocation amount.

Abstract: Embodiments relate to supporting transaction data committed to a stable storage. Committed data in the cluster is stored in the persistent cache layer and replicated and stored in the cache layer of one or more secondary nodes. One copy is designated as a master copy and all other copies are designated as replica, with an exclusive write lock assigned to the master and a shared write lock extended to the replica. An acknowledgement of receiving the data is communicated following confirmation that the data has been replicated to each node designated to receive the replica. Managers and a director are provided to support management of the master copy and the replicas within the file system, including invalidation of replicas, fault tolerance associated with failure of a node holding a master copy, recovery from a failed node, recovered of the file system from a power failure, and transferring master and replica copies within the file system.

Abstract: Systems for memory management in virtual machines. A method embodiment forms a reconfigurable multi-level data structure by requesting reserved memory as well as loaned-out memory. The method configures the multi-level data structure to have a first area comprising reserved memory and having a second area comprising reconfigurable memory. The reserved memory portion of the data structure is populated with pointers that address one or more portions of the second area. During operation, the method receives a request to release some or all of the reconfigurable memory. Memory address pointers in the first portion of the multi-level data structure are modified to reflect the release of the reconfigurable memory. In a hypervisor-based virtual machine environment, the first area comprising reserved memory can be allocated via a hypervisor call. The second area comprising reconfigurable memory is allocated via a balloon memory driver call.

Abstract: An architecture for implementing a distributed metadata system in a virtualization environment comprising a plurality of servers, wherein each server may access and operate upon the entirety of the metadata in the virtualization environment. In response to a request received at a server to operate upon the metadata, existing metadata associated with the request is read by the server. The server performs one or more updates based upon the retrieved metadata, and attempts to update the corresponding stored metadata. In some embodiments, attempting to update the stored metadata comprises reading the metadata again and comparing it to the originally retrieved metadata, and performing the update only if the newly retrieved metadata matches the originally retrieved metadata.

Abstract: A method for managing storage allocation includes adaptively determining, by a storage device processor, a region width across disk spaces for a group of storage devices that is inversely proportional to a number of nodes sharing a particular storage device. An adaptive storage device allocation region of the particular storage device is created based on the determined region width across the disk spaces for the group of storage devices.

Abstract: Techniques are disclosed for peer-to-peer data transfers where a source device receives a request to read data words from a target device. The source device creates a first and second read command for reading a first portion and a second portion of a plurality of data words from the target device, respectively. The source device transmits the first read command to the target device, and, before a first read operation associated with the first read command is complete, transmits the second read command to the target device. The first and second portions of the plurality of data words are stored in a first and second portion a buffer memory, respectively. Advantageously, an arbitrary number of multiple read operations may be in progress at a given time without using multiple peer-to-peer memory buffers. Performance for large data block transfers is improved without consuming peer-to-peer memory buffers needed by other peer GPUs.

Abstract: Systems for high-performance computing. A storage control architecture is implemented by a plurality of nodes, where a node comprises combinations of executable containers that execute in cooperation with virtual machines running above a hypervisor. The containers run in a virtual machine above a hypervisor, and/or can be integrated directly into the operating system of a host node. Sensitive information such as credit card information may be isolated from the containers in a separate virtual machine that is configured to be threat resistant, and which can be accessed through a threat resistant interface module. One of the virtual machines of the node may be a node-specific control virtual machine that is configured to operate as a dedicated storage controller for a node. One of the virtual machines of the node may be a node-specific container service machine that is configured to provide storage-related and other support to a hosted executable container.

Abstract: Embodiments of the invention relate to supporting transaction data committed to a stable storage. Committed data in the cluster is stored in the persistent cache layer and replicated and stored in the cache layer of one or more secondary nodes. One copy is designated as a master copy and all other copies are designated as replica, with an exclusive write lock assigned to the master and a shared write lock extended to the replica. An acknowledgement of receiving the data is communicated following confirmation that the data has been replicated to each node designated to receive the replica. Managers and a director are provided to support management of the master copy and the replicas within the file system, including invalidation of replicas, fault tolerance associated with failure of a node holding a master copy, recovery from a failed node, recovered of the file system from a power failure, and transferring master and replica copies within the file system.

Abstract: A method for managing storage allocation includes adaptively determining, by a storage device processor, a region width across disk spaces for a group of storage devices that is inversely proportional to a number of nodes sharing a particular storage device. An adaptive storage device allocation region of the particular storage device is created based on the determined region width across the disk spaces for the group of storage devices.

Abstract: Embodiments of the invention relate to storage allocation in a storage system. One embodiment includes adaptively determining, by a storage device processor, a region height across disk spaces of a group of storage devices that is proportional to a number of connected storage devices. The storage device processor adaptively determines a region width across the disk spaces for the group of storage devices that is inversely proportional to a number of nodes sharing a particular storage device.

Abstract: The embodiments described herein relate to synchronization of data in a shared pool of configurable computer resources. One or more consistency points are created in a source filesystem. A first consistency point is compared with a second consistency point to detect a directory change at the source filesystem, which includes identifying at least one difference between the first and second consistency points. A file level change associated with an established directory at a target filesystem is identified responsive to the detection of the directory change. A link is established between the source filesystem and the target filesystem, and the established directory is updated based on the file level change.

Abstract: A system, method, and computer program product are provided for implementing asymmetric AES-CBC (Advanced Encryption Standard-Cipher Block Chaining) channels usage between encryption and decryption of data. In operation, data to be written to memory is identified. In addition, the data is encrypted utilizing a first AES-CBC channel. Additionally, at least one of a plurality of AES-CBC channels is utilized to decrypt the data to achieve a determined performance target.

Abstract: A system, method, and computer program product for recovering from a memory underflow condition associated with generating video signals are disclosed. The method includes the steps of determining that a first counter is greater than a second counter, incrementing an address corresponding to a memory fetch request by an offset, and issuing the memory fetch request to a memory. The first counter represents a number of pixels that have been read by a display pipeline for a current frame and the second counter represents a number of pixels requested from a memory for the current frame.

Abstract: Embodiments of the invention relate to synchronization of data in a shared pool of configurable computer resources. An image of the filesystem changes, including data and metadata, is captured in the form of a consistency point. Sequential consistency points are created, with changes to data and metadata in the filesystem between sequential consistency captured and placed in a queue for communication to a target filesystem at a target site. The changes are communicated as a filesystem operation, with the communication limited to the changes captured and reflected in the consistency point.

Abstract: Embodiments relate to supporting transaction data committed to a stable storage. Committed data in the cluster is stored in the persistent cache layer and replicated and stored in the cache layer of one or more secondary nodes. One copy is designated as a master copy and all other copies are designated as replica, with an exclusive write lock assigned to the master and a shared write lock extended to the replica. An acknowledgement of receiving the data is communicated following confirmation that the data has been replicated to each node designated to receive the replica. Managers and a director are provided to support management of the master copy and the replicas within the file system, including invalidation of replicas, fault tolerance associated with failure of a node holding a master copy, recovery from a failed node, recovered of the file system from a power failure, and transferring master and replica copies within the file system.

Abstract: Embodiments of the invention relate to storage allocation in a storage system. One embodiment includes adaptively determining, by a storage device processor, a region height across disk spaces of a group of storage devices that is proportional to a number of connected storage devices. The storage device processor adaptively determines a region width across the disk spaces for the group of storage devices that is inversely proportional to a number of nodes sharing a particular storage device.

Abstract: Embodiments of the invention relate to supporting transaction data committed to a stable storage. Committed data in the cluster is stored in the persistent cache layer and replicated and stored in the cache layer of one or more secondary nodes. One copy is designated as a master copy and all other copies are designated as replica, with an exclusive write lock assigned to the master and a shared write lock extended to the replica. An acknowledgement of receiving the data is communicated following confirmation that the data has been replicated to each node designated to receive the replica. Managers and a director are provided to support management of the master copy and the replicas within the file system, including invalidation of replicas, fault tolerance associated with failure of a node holding a master copy, recovery from a failed node, recovered of the file system from a power failure, and transferring master and replica copies within the file system.

Abstract: Embodiments of the invention relate to efficiently employing checksums for shared nothing clustered filesystems. Tools are provided to compute the checksum in response to a read transaction and to utilize the computed checksum to prevent serving corrupted data. Multiple levels of data replication are provided. The checksum computation functions within the multiple levels and addresses a specified data block that is the subject of the read transaction.