A system and method for distributing data over a plurality of remote storage nodes. Data are split into segments and each segment is encoded into a number of codeword chunks. None of the codeword chunks contains any of the segments. Each codeword chunk is packaged with at least one encoding parameter and identifier, and metadata are generated for at least one file and for related segments of the at least one file. The metadata contains information to reconstruct from the segments, and information for reconstructing from corresponding packages. Further, metadata are encoded into package(s), and correspond to a respective security level and a protection against storage node failure. A plurality of packages are assigned to remote storage nodes to optimize workload distribution. Each package is transmitted to at least one respective storage node as a function iteratively accessing and retrieving the packages of metadata and file data.

For serving sequential read patterns from a compressed journal storage system, a construction area cache algorithm is used to temporarily store the read and decompressed data in a user view sequential order to minimize disk I/Os and CPU utilization while serving the data to the user.

A method, system and computer program product are provided for implementing coherent accelerator function isolation for virtualization in an input/output (IO) adapter in a computer system. A coherent accelerator provides accelerator function units (AFUs), each AFU is adapted to operate independently of the other AFUs to perform a computing task that can be implemented within application software on a processor. The AFU has access to system memory bound to the application software and is adapted to make copies of that memory within AFU memory-cache in the AFU. As part of this memory coherency domain, each of the AFU memory-cache and processor memory-cache is adapted to be aware of changes to data commonly in either cache as well as data changed in memory of which the respective cache contains a copy.

Described are techniques for destaging data. Write data for write operations are stored in cache page(s). The cache may be partitioned into cache pages and write data stored thereon may be marked as write pending denoting that write data needs to be written out to physical storage. Weight values may be determined for the cache pages in accordance with factors. A first cache page may be selected having a highest such weight value where the selected first cache page includes at least some write data marked as write pending. The write data of the selected first cache page may be destaged to physical storage.

Systems, apparatuses, and methods related to a write-back cache policy to limit data transfer time to a memory device are described. A controller can orchestrate performance of operations to write data to a cache according to a write-back policy and write addresses associated with the data to a buffer. The controller can further orchestrate performance of operations to limit an amount of data stored by the buffer and/or a quantity of addresses stored in the buffer. In response to a power failure, the controller can cause the data stored in the cache to be flushed to a persistent memory device in communication with the cache.

A system shares I/O load between controllers in a high availability system. For writes, a controller determines based on one or more factors which controller will flush batches of data from write-back cache to better distribute the I/O burden. The determination occurs after the local storage controller caches the data, mirrors it, and confirms write complete to the host. Once it is determined which storage controller will flush the cache, the flush occurs and the corresponding metadata at a second layer of indirection is updated by that determined storage controller (whether or not it is identified as the owner of the corresponding volume to the host, while the volume owner updates metadata at a first layer of indirection). For a host read, the controller that owns the volume accesses the metadata from whichever controller(s) flushed the data previously and reads the data, regardless of which controller had performed the flush.

A method for demoting data from a cache comprising heterogeneous memory types is disclosed. The method maintains, for a data element in the cache, a write access count that is incremented each time the data element is updated in the cache. The cache includes a higher performance portion and a lower performance portion. The method removes the data element from the higher performance portion in accordance with a cache demotion algorithm. If the data element also resides in the lower performance portion and the write access count is below a first threshold, the method leaves the data element in the lower performance portion. If the data element also resides in the lower performance portion and the write access count is at or above the first threshold, the method removes the data element from the lower performance portion. A corresponding system and computer program product are also disclosed.

Secure memory repartitioning technologies are described. Embodiments of the disclosure may include a processing device including a processor core and a memory controller coupled between the processor core and a memory device. The memory device includes a memory range including a section of convertible pages that are convertible to secure pages or non-secure pages. The processor core is to receive a non-secure access request to a page in the memory device, responsive to a determination, based on one or more secure state bits in one or more secure state bit arrays, that the page is a secure page, insert an abort page address into a translation lookaside buffer, and responsive to a determination, based on the one or more secure state bits in the one or more secure state bit arrays, that the page is a non-secure page, insert the page into the translation lookaside buffer.

A method for depopulating data from cache includes receiving a command to depopulate the cache of selected data. The command has an application identifier as a parameter. The application identifier is associated with an application that previously accessed the data. The method searches the cache for data elements that are marked with the application identifier and removes the data elements from the cache. In certain embodiments, the data elements are marked with a first application identifier associated with an application that staged the data elements into the cache, and a second application identifier associated with an application that last accessed the data elements. In certain embodiments, removing the data elements from the cache comprises only removing the data elements from the cache if the application identifier matches one or more of the first application identifier and the second application identifier. A corresponding system and computer program product are also disclosed.

A method for demoting data from a cache comprising heterogeneous memory types is disclosed. The method maintains for a data element in the cache, a write access count that is incremented each time the data element is updated in the cache. The cache includes a higher performance portion and a lower performance portion. The method also maintains, for the data element, a read access count that is incremented each time a data element is read in the cache. The method removes the data element from the higher performance portion of the cache in accordance with a cache demotion algorithm. If the write access count is below a first threshold and the read access count is above a second threshold, the method places the data element in the lower performance portion. A corresponding system and computer program product are also disclosed.