Abstract: Techniques provide communications bandwidth between storage processors (SPs). Such techniques involve electrically coupling the SPs with a first side of a midplane. Such techniques further involve electrically coupling a network interface controller (NIC) device with a second side of the midplane that is opposite the first side of the midplane. Such techniques further involve configuring the NIC device to convey communications between the SPs while the SPs are electrically coupled with the first side of the midplane and while the NIC device is electrically coupled with the second side of the midplane that is opposite the first side of the midplane.

Abstract: A method is provided for use in a storage processor, the method comprising: receiving a write request, the write request including a request to store user data in an array that includes a plurality of solid-state drives (SSD); executing the write request by: identifying metadata that is associated with the write request, and writing the user data and the metadata to different data streams that are opened on the plurality of SSDs; wherein writing the user data and the metadata to different data streams causes: (i) the user data to be stored in one or more first erase units of any of the plurality of SSDs, and (ii) the metadata to be stored in one or more second erase units of any of the plurality of SSDs, such that no part of the metadata is stored on any of the one or more first erase units, and no part of the user data is stored on any of the one or more second erase units.

Abstract: Regulating maintenance background (BG) task activity using instrumented waiting points (WPs) can include: collecting feedback metrics for the WPs, where each WP is instrumented to collect a set of feedback metrics including an average waiting time and a first value denoting a portion of resource requests received at the WP which are from maintenance BG tasks; determining, in accordance with criteria and collected feedback metrics, whether the criteria is true for at least a first WP associated with a set of feedback metrics, wherein the criteria includes determining whether the first WP has an associated average waiting time of the set which exceeds a waiting time threshold, and whether the first WP has a share of maintenance BG requests exceeding a minimum; and responsive to determining that the criteria is true for at least the first WP, performing processing to reduce a current activity level of said maintenance BG tasks.

Abstract: Techniques for analyzing cache efficiencies in storage systems based on in-depth metrics instrumentation. The techniques include collecting metrics instrumentation data for each page of a specific type stored in a cache memory component of a storage system. The metrics instrumentation data for each page of a specific type includes a timestamp indicating when the page was stored in the cache, a timestamp indicating when the last cache hit occurred for the page, a current number of cache hits for the page, and an indication of the specific type of page. The techniques further include, based on the metrics instrumentation data, obtaining a plurality of metrics for each specific type of page stored in the cache. The techniques further include, based on the plurality of metrics and/or the metrics instrumentation data, performing a remedial action to improve performance of the cache memory component or provide more optimal use of memory resources.

Abstract: At least one processing device comprises a processor and a memory coupled to the processor. The at least one processing device is configured to associate different classes of service with respective threads of one or more applications executing on at least one of a plurality of processing cores of a storage system, to configure different sets of prioritized thread queues for respective ones of the different classes of service, to enqueue particular ones of the threads associated with particular ones of the classes of service in corresponding ones of the prioritized thread queues, and to implement different dequeuing policies for selecting particular ones of the enqueued threads from the different sets of prioritized thread queues based at least in part on the different classes of service. The at least one processing device illustratively comprises at least a subset of the plurality of processing cores of the storage system.

Abstract: At least one processing device comprises a processor and a memory coupled to the processor. The at least one processing device is configured to establish one or more groups of synchronization objects in a storage system based at least in part on object type, and for each of the one or more groups, to insert entries into a corresponding object type queue for respective objects of the group, to execute a monitor thread for the group, the monitor thread being configured to scan the entries of the corresponding object type queue, and responsive to at least one of the scanned entries meeting one or more designated conditions, to take at least one automated action for its associated object. The synchronization objects illustratively comprise respective locks, or other objects. The at least one processing device illustratively comprises at least a subset of a plurality of processing cores of the storage system.

Abstract: A storage system in one embodiment comprises a front-end device and a first storage node corresponding to the front-end device. The first storage node comprises a processor that is separate from the front-end device. The front-end device is configured to obtain a write operation that comprises at least a first block of data and to calculate a hash digest based at least in part on the first block of data. The front-end device is configured to provide the hash digest to the processor. The processor is configured to identify a first data page that comprises a second block of data that is a target for replacement by the first block of data and to identify a second storage node based at least in part on the first data page. The processor is configured to transmit the hash digest to the second storage node.

Abstract: A method, computer program product, and computing system for defining a queue. The queue may be based on a linked list and may be a first-in, first-out (FIFO) queue that may be configured to be use used with multiple producers and a single consumer. The queue may include a plurality of queue elements. A tail element and a head element may be defined from the plurality of elements within the queue. The tail element may point to a last element of the plurality of elements and the head element may point to a first element of a plurality of elements. An element may be dequeued from the tail element, which may include determining if the tail element is in a null state. An element may be enqueued to the head element, which may include adding a new element to the queue.

Abstract: A technique protects user data within a storage system. The technique involves, in response to a request signal that directs the storage system to store the user data, generating first parity and second parity based on the user data. The technique further involves storing the first parity and the user data in a data uber of the storage system, the data uber providing redundant array of independent disks (RAID) protection. The technique further involves storing the second parity in designated free storage of the storage system, the designated free storage being separate from the data uber.

Abstract: A technique garbage collects user data within a storage system. The technique involves, in response to a request signal that directs the storage system to garbage collect user data, coalescing first user data and second user data to form new user data. The technique further involves generating first parity and second parity based on the new user data. The technique further involves storing the first parity and the new user data in a data uber of the storage system, the data uber providing redundant array of independent disks (RAID) protection. The technique further involves storing the second parity in designated free storage of the storage system, the designated free storage being separate from the data uber.

Abstract: A file storage application that processes file operations is communicably connected with a block storage application that processes block operations by establishing multiple communication sessions between the file storage application and the block storage application. Multiple logical volumes provided by the block storage application are exposed to the file storage application over the multiple communication sessions established between the file storage application and the block storage application using a total number of logical paths to the logical volumes that is equivalent to the total number of the logical volumes provided by the block storage application to the file storage application.

Abstract: A method, computer program product, and computer system for identifying, by a computing device, storage containers that contain cold data. At least a portion of the storage containers may be processed to determine whether a first compression technique will result in a higher level of compression above a threshold level of compression than a second compression technique. The storage containers may be processed using the first compression technique based upon, at least in part, determining that the first compression technique will result in the higher level of compression above the threshold level of compression than the second compression technique.

Abstract: A method, computer program product, and computing system for defining an affined OS-thread on each core of a multicore microprocessor, thus defining a plurality of affined OS-threads; executing a sequentially-activated polling thread on each of the affined OS-threads, wherein the sequentially-activated polling thread is configured to detect waiting IO activity on IO interfaces associated with the affined OS-threads; and if waiting IO activity is detected, activating one or more X-threads on a specific affined OS-thread that is associated with a specific IO interface on which the waiting IO activity was detected.

Abstract: An apparatus comprises at least one processing device that includes a processor coupled to a memory, and is configured to monitor latencies associated with processing of input-output operations in a plurality of storage nodes of a distributed storage system, to detect an unbalanced condition between the storage nodes based at least in part on the monitored latencies, and responsive to the detected unbalanced condition, to adjust an assignment of slices of a logical address space of the distributed storage system to the storage nodes. Adjusting the assignment of slices of the logical address space of the distributed storage system to the storage nodes responsive to the detected unbalanced condition illustratively comprises increasing a number of the slices assigned to one or more of the storage nodes having relatively low latencies and decreasing a number of slices assigned to one or more of the storage nodes having relatively high latencies.

Abstract: An apparatus in one embodiment comprises at least one processing device comprising a processor coupled to a memory, with the processing device being configured to detect a failure of at least one storage node that impacts a write cache destaging process in a distributed content addressable storage (CAS) system comprising a plurality of storage nodes each associated with one or more storage devices. Responsive to the detected failure, the processing device issues one or more write cache metadata preload commands to direct one or more other ones of the storage nodes to preload from their associated storage devices metadata characterizing one or more data pages that are subject to the write cache destaging process, thereby illustratively reducing address lock contention in the CAS system. The processing device illustratively comprises at least a portion of a distributed storage controller of the CAS system. Other embodiments include methods and computer program products.

Abstract: Techniques for performing data transfers may include determining a first page of user data to be transferred from a source data storage system to a target data storage system, wherein the source data storage system has a source page size granularity denoting a first size of backend I/O operations on the source data storage system, wherein the target data storage system has a target page size granularity denoting a second size of backend I/O operations on the target data storage system; performing processing on the source data storage system that constructs a second page of user data that is the second size, wherein the second page of user data includes the first page of user data that is the first size and another page of user data that is the first size; and transferring the second page of user data from the source to the target data storage system.

Abstract: At least one processing device comprises a processor and a memory coupled to the processor. The at least one processing device is configured to implement adaptive flow control in conjunction with processing of input-output operations in a storage system. The adaptive flow control comprises a first feedback loop in which a window size defining an amount of concurrent processing of the input-output operations in the storage system is adjusted responsive to a measured latency for processing of one or more of the input-output operations. The adaptive flow control further comprises a second feedback loop in which at least one latency threshold used to control adjustment of the window size in the first feedback loop is adjusted. The at least one processing device illustratively comprises at least one processing core of a multi-core storage node of a distributed storage system.

Abstract: A method of managing operation of a computing device is provided. The method includes (a) running a system scheduler that schedules execution of a first application and a second application on a central processing unit (CPU) core of the computing device; (b) while the first application is executing on the core, detecting, by the first application, a context-switch opportunity; and (c) issuing, by the first application in response to detecting the context-switch opportunity, a blocking operation that triggers the system scheduler to perform a rescheduling operation between the first and second applications on the CPU core. An apparatus, system, and computer program product for performing a similar method are also provided.

Abstract: A technique is disclosed for generating rebuild data of a RAID configuration having one or more failed drives. The RAID configuration includes multiple sets of drives coupled to respective computing nodes, and the computing nodes are coupled together via a network. A lead node directs rebuild activities, communicating with the other node or nodes and directing such node(s) to compute partial rebuild results. The partial rebuild results are based on data of the drives of the RAID configuration coupled to the other node(s). The lead node receives the partial rebuild results over the network and computes complete rebuild data based at least in part on the partial rebuild results.

Abstract: A method comprises maintaining stripe metadata corresponding to stripes of data stored on a plurality of storage devices. The stripe metadata comprises a first timestamp, a second timestamp and a read count for each stripe. The method comprises obtaining a read request associated with a given stripe and having an associated timestamp and determining whether or not a time period for the given stripe has been exceeded. The method comprises updating the stripe metadata corresponding to the given stripe based at least in part on the determination and the associated timestamp and determining a read access frequency of the given stripe based at least in part on the read count, the first timestamp and the second timestamp of the updated stripe metadata. The method comprises performing at least one of a defragmentation process and a rebuild process based at least in part on the determined read access frequency.