Abstract: A method, computer program product, and computing system for sensing a failure within a system within a computing device. The system may include a cache memory system and a vaulted memory comprising a random access memory (RAM) having a plurality of independent persistent areas. A primary node and secondary node may be provided. The primary node may occupy a first independent persistent area of the RAM of the vaulted memory. The secondary node may occupy a second independent persistent area of the RAM of the vaulted memory. Data within the vaulted memory may be written to a persistent media using an iterator. The data may include at least one dirty page. Writing data within the vaulted memory to the persistent media may include flushing the at least one dirty page to the persistent media.

Abstract: A method, computer program product, and computing system for generating a page buffer pool within a data journal of a storage node. A plurality of TO operations may be processed on a storage array using the storage node. A plurality of pages may be persisted in a plurality of page buffers within the page buffer pool based upon, at least in part, the processing of the plurality of TO operations. For each page buffer in the page buffer pool, a hash of the page buffer may be generated, thus defining a page buffer hash. The page buffer hash may be stored in a page descriptor associated with the page buffer.

Abstract: In a log based system, a reclamation list of cache pages containing dirty data can be maintained and used. The cached dirty data pages identified by the reclamation list can be candidates for eviction from the cache. A cached dirty data page on the reclamation list can be persistently logged in a transaction log extension having storage allocated from a non-volatile solid state drive (SSD). The reclamation list can include descriptors of the cached dirty data pages prioritized for eviction in accordance with a least recently used (LRU) policy so that the LRU cached dirty data page can be selected for eviction. When a dirty data page which was evicted from the cache is reloaded into cache, the dirty data page can be added to the reclamation list by adding its page descriptor to the reclamation list. A dirty data page can be removed from the reclamation list once flushed.

Abstract: In a log based system, a reclamation list of cache pages containing dirty data can be maintained and used. The cached dirty data pages identified by the reclamation list can be candidates for eviction from the cache. A cached dirty data page on the reclamation list can be persistently logged in a transaction log extension having storage allocated from a non-volatile solid state drive (SSD). The reclamation list can include descriptors of the cached dirty data pages prioritized for eviction in accordance with a least recently used (LRU) policy so that the LRU cached dirty data page can be selected for eviction. When a dirty data page which was evicted from the cache is reloaded into cache, the dirty data page can be added to the reclamation list by adding its page descriptor to the reclamation list. A dirty data page can be removed from the reclamation list once flushed.

Abstract: A method may use memory efficiently to extend cache. A processor receives a request to write data. The size of the data in the write request is compared to a threshold. When the size of the data exceeds the threshold, the data is stored on a solid state device. Page descriptors for the data on the solid state device are stored in a metadata log, and a reference to a first page descriptor of the page descriptors in the metadata log is stored in a first hash table in memory.

Abstract: Techniques for rebuilding data in a data storage system are provided. A method includes: (a) identifying (i) a first set of degraded Ubers that contain no portions reserved for direct writing and (ii) a second set of degraded Ubers that contain at least one portion reserved for direct writing. Direct writing is a process that writes blocks to long-term storage prior to mapping those blocks in a metadata mapping structure. An Uber is a set of adjacent stripes across a respective Redundant Array of Independent Disks (RAID) array of the data storage system, and a degraded Uber is an Uber that includes at least one failed drive within its RAID array. The method further includes (b) initiating a rebuild of the first set of degraded Ubers; and (c) delaying a rebuild of each degraded Uber of the second set until all pending direct writes to blocks of that degraded Uber have been mapped by the metadata mapping structure.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, a plurality of IO requests. A portion of the plurality of IO requests may be aggregated based upon a block size. The portion of the plurality of IO requests may be committed to persistent storage in a batch based upon, at least in part, aggregating the portion of the plurality of IO requests based upon the block size.

Abstract: A method may use memory efficiently to extend cache. A processor receives a request to write data. The size of the data in the write request is compared to a threshold. When the size of the data exceeds the threshold, the data is stored on a solid state device. Page descriptors for the data on the solid state device are stored in a metadata log, and a reference to a first page descriptor of the page descriptors in the metadata log is stored in a first hash table in memory.

Abstract: A method, computer program product, and computing system for receiving, at a local node, a request to buffer data on a remote persistent cache memory system of a remote node. A target memory address within the remote persistent cache memory system may be sent from the local node via a remote procedure call (RPC). The data may be sent from the local node to the target memory address within the remote persistent cache memory system via a remote direct memory access (RDMA) command.

Abstract: A method, computer program product, and computing system for sensing a failure within a system within a computing device. The system may include a cache memory system and a vaulted memory comprising a random access memory (RAM) having a plurality of independent persistent areas. A primary node and secondary node may be provided. The primary node may occupy a first independent persistent area of the RAM of the vaulted memory. The secondary node may occupy a second independent persistent area of the RAM of the vaulted memory. Data within the vaulted memory may be written to a persistent media using an iterator. The data may include at least one dirty page. Writing data within the vaulted memory to the persistent media may include flushing the at least one dirty page to the persistent media.

Abstract: Write operation may be persistently recorded in a log using PDESC (page descriptor)-PB (page block) pairs. The PDESC-PB pairs of the log may be flushed. Flushing the log may include: determining a working set of PDESC-PB pairs; partitioning the working set into buckets by mapping each PDESC-PB pair of the working set to a bucket using a function; flushing a portion of the PDESC-PB pairs of a first bucket of the working set; updating, at a point in time, a first BHFS (bucket highest flushed sequence ID) value for the first bucket, wherein the first BHFS denotes a first sequence ID and each sequence ID associated with a PDESC-PB pair of the portion flushed prior to the point in time is less than the first sequence ID; and reclaiming PBs of the portion. As part of recovery processing, BHFSs for the buckets may be used to detect invalid PDESCs.

Abstract: Techniques for providing hiccup-less failback and journal recovery. The techniques include determining a head position of a data log of a primary node and placing a marker at a corresponding position in a data log of a secondary node. In response to an IO request, the head of the primary log is moved to allocate space for writing a data entry, and the secondary node is directed to move a head of the secondary log to allocate space for writing the data entry. In response to a data entry being flushed from the primary node, a tail of the primary log is moved to reclaim allocated space for a previous data entry, and the secondary node is directed to move a tail of the secondary log to reclaim previously allocated space. In response to a tail of the secondary log coinciding with the marker position, content of the logs is synchronized.

Abstract: Techniques for providing hiccup-less failback and journal recovery. The techniques include determining a head position of a data log of a primary node and placing a marker at a corresponding position in a data log of a secondary node. In response to an IO request, the head of the primary log is moved to allocate space for writing a data entry, and the secondary node is directed to move a head of the secondary log to allocate space for writing the data entry. In response to a data entry being flushed from the primary node, a tail of the primary log is moved to reclaim allocated space for a previous data entry, and the secondary node is directed to move a tail of the secondary log to reclaim previously allocated space. In response to a tail of the secondary log coinciding with the marker position, content of the logs is synchronized.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, an IO request on a first node. It may be determined whether a virtual address for the IO request is in a virtual cache. A read to RAID may be issued using the virtual address when the virtual address for the IO request is not in the virtual cache. A return of a cached page associated with the virtual address may be issued when the virtual address for the IO request is in the virtual cache.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, an IO request on a first node. It may be determined whether a virtual address for the IO request is in a virtual cache. A read to RAID may be issued using the virtual address when the virtual address for the IO request is not in the virtual cache. A return of a cached page associated with the virtual address may be issued when the virtual address for the IO request is in the virtual cache.

Abstract: A storage system in one embodiment comprises a plurality of storage devices storing data pages. Each data page has a content-based signature derived from that data page. The content-based signatures are associated with physical locations storing the data pages. In response to receipt of a write input/output (IO) request that includes a data segment that is smaller than a page granularity of the storage devices, a content-based signature associated with the data segment is determined which also corresponds to a target data page stored at one of the physical locations. In response to determining the content-based signature, an inflight write count corresponding to the content-based signature is incremented. In response to a decrement request to decrement a reference count of the physical location corresponding to the content-based signature, a decrement flag corresponding to the content-based signature is set in the data structure and the decrement request is postponed.

Abstract: A control module of a clustered storage system in one embodiment is configured to receive a write request for a data block of a page, to retrieve an existing content-based signature for the page, to identify from the existing content-based signature a first one of the data modules currently storing the page, and to compute a content-based signature of the data block. The control module is further configured to send the content-based signature of the data block to the first data module, to receive from the first data module an updated content-based signature for the page computed utilizing the content-based signature of the data block, to identify from the updated content-based signature a second one of the data modules that will store the page as updated to include the data block, and to provide information regarding the data block and the updated content-based signature to the second data module for utilization in storage of the updated page.

Abstract: A storage system in one embodiment comprises a plurality of storage devices storing data pages. Each data page has a content-based signature derived from that data page. The content-based signatures are associated with physical locations storing the data pages. In response to receipt of a write input/output (IO) request that includes a data segment that is smaller than a page granularity of the storage devices, a content-based signature associated with the data segment is determined which also corresponds to a target data page stored at one of the physical locations. In response to determining the content-based signature, an inflight write count corresponding to the content-based signature is incremented. In response to a decrement request to decrement a reference count of the physical location corresponding to the content-based signature, a decrement flag corresponding to the content-based signature is set in the data structure and the decrement request is postponed.

Abstract: A method, non-transitory computer readable medium, security management apparatus, and network traffic management system that monitors received HTTP requests associated with a source IP address to obtain data for one or more signals. A value for one or more bins corresponding to one or more of the signals for individual behavioral histograms and a global behavioral histogram is updated based on the signal data. The individual behavioral histograms each correspond to one of the source IP addresses. A determination is made when a DDoS attack condition is detected. When the determining indicates that the DDoS attack condition is detected, an attack pattern is identified in the global behavioral histogram and a mitigation action is initiated for one of the source IP addresses based on a correlation of one of the individual behavioral histograms, which corresponds to the one of the source IP addresses, to the attack pattern.

Abstract: A storage system in one embodiment comprises a plurality of storage devices storing data pages. Each data page has a content-based signature derived from that data page. The content-based signatures are associated with physical locations storing the data pages. In response to receipt of a write input/output (IO) request that includes a data segment that is smaller than a page granularity of the storage devices, a content-based signature associated with the data segment is determined which also corresponds to a target data page stored at one of the physical locations. In response to determining the content-based signature, an inflight write count corresponding to the content-based signature is incremented. In response to a decrement request to decrement a reference count of the physical location corresponding to the content-based signature, a decrement flag corresponding to the content-based signature is set in the data structure and the decrement request is postponed.