Emc IP Holding Company LLC

Emc Corporation

Dell Products Inc.

Dell & Products L.p.

Ashok Tamilarasan

Vamsi K Vankamamidi

Philippe Armangau

Michael Manning

Peter Puhov

Ronald D Proulx

Wayne E Garrett, Jr

Amitai Alkalay

Robert Foley

Brion Patrick Philbin

Eric Petsching

Geng Han

Lili Chen

Thomas N Dibb

James W Espy

Naizhong Chiu

Samuel L Mullis, Ii

John F Gillono

Vikram A Prabhakar

Mahadevan Vasudevan

Zhiqi Liu

Ying Guo

Phillip P Fultz

Pavan Kumar Vutukuri

Joseph Perry

Dmitri Prilepski

Naizhong Chiu (Qiu)

Gregory Bailey

Naizhong Qiu

In at least one embodiment, processing can include: partitioning a first set of CPU cores into a plurality of CPU core subsets each associated with a single corresponding one of a plurality of predefined I/O types; classifying each of a plurality of I/O requests as one of the plurality of predefined I/O types; for each of the plurality of I/O requests, selecting a CPU core from a first CPU core subset of the plurality of CPU core subsets based, at least in part, on the first CPU core subset having a corresponding one of the plurality of predefined I/O types that matches an associated one of the plurality of predefined I/O types of said each I/O request; and processing the plurality of I/O requests on their selected CPU cores.

Techniques for CPU core management based on operation types

Techniques can include: receiving, at a first node, a read I/O directed to a logical address; determining that the first node does not own the logical address; sending over an interconnect a redirect request from the first node to a second node that owns the first logical address; and the second node performing processing including: determining, in accordance with one or more criteria, whether the interconnect is overloaded; responsive to determining that the interconnect is not overloaded, sending a redirect reply over the interconnect to the first node where the redirect reply includes first content stored at the first logical address; and responsive to determining that the interconnect is overloaded, sending the redirect reply over the interconnect to the first node where the redirect reply includes physical location information identifying a first physical storage location or address on non-volatile storage of the first content of the first logical address.

I/O processing techniques in a multi-node system

A technique for managing a mapping structure in a data storage system includes identifying levels in the mapping structure of pages to be removed and estimating the workload required for removing the pages based at least in part on the identified levels. The technique further includes initiating processing of the pages based at least in part on the estimated workload.

Processing pages marked for deletion

A method of managing CPU cores in a data storage apparatus (DSA) configured to perform both host I/O (Input/Output) processing and background storage processing is provided. The method includes (a) selectively classifying background storage tasks in one of a first classification for longer-running tasks and a second classification for shorter-running tasks; (b) selecting CPU cores that are running fewer than a threshold number of first-classification background tasks to process host I/O requests; and (c) processing the host I/O requests on their selected CPU cores. An apparatus, system, and computer program product for performing a similar method are also provided.

Techniques for managing cores for storage

Caching techniques can include: receiving, from a host, a read I/O operation requesting to read from a logical address; determining whether a mapping cache includes a descriptor corresponding to the logical address; and responsive to determining the mapping cache includes the descriptor corresponding to the logical address, performing read hit mapping cache processing including: obtaining physical location information from the descriptor, wherein the physical location information identifies a physical location on non-volatile storage including first content stored at the logical address; reading, using the physical location information, the first content from the physical location; performing validation processing to validate the first content using a hash value included in the descriptor; and responsive to validation processing successfully validating the first content, returning the first content to the host.

Caching techniques using a mapping cache and maintaining cache coherency using hash values

A data storage system can include a deduplicated data cache used to store unique deduplicated data portions. Data portions can be promoted to the deduplicated data cache in connection with servicing I/O operations. Servicing the I/O operation that reads data from, or writes data to, a logical address can include determining whether a data portion stored at the logical address meets criteria for promoting the data portion to a deduplicated data cache. The criteria can include a condition that the data portion is a duplicate of content stored at multiple logical addresses, and can include a condition that the data portion has a reference count that is at least a minimum threshold where the reference count denotes a number of logical addresses at which the data portion is stored. Responsive to determining the data portion meets the criteria, the data portion can be stored in the deduplicated data cache.

Caching techniques using a data deduplication cache and a data cache

Caching techniques can include: receiving a read I/O operation requesting to read from a logical address; determining whether a mapping cache includes a descriptor for the logical address, the mapping cache including two hash tables; responsive to determining that the mapping cache includes the descriptor for the logical address, performing read hit mapping cache processing which includes using a physical location identified by the descriptor to read content stored at the logical address; and responsive to determining that the mapping cache does not include the descriptor for the logical address, performing read miss mapping cache processing which includes adding the descriptor to the mapping cache. Read miss mapping cache processing can include adding the descriptor to a first hash table, used to access the descriptor by the logical address, and adding the descriptor to a second hash table used to access the descriptor by the physical location.

Caching techniques using a mapping cache and maintaining cache coherency using physical to logical address mapping

A method is used for managing overlapping communications regarding downtiering and invalidating cached data among nodes in a storage system. The method includes identifying, by a node, data to downtier. The node adds the data to an in progress table, and sends a request for permission to downtier the data to a peer node. The node receives permission from the peer node to downtier the data. In response to the permission to downtier the data, the node checks the in progress table for the data and takes an action based on a result of checking the in progress table.

Managing overlapping communications between downtiering and invalidating cached data among nodes in a storage system

Techniques are used for identifying allocated blocks in a storage system. The techniques may be used to provide, among other things, retrieval of a value associated with a most recent reinitialization of the storage system. For a tier of user data storage in the storage system, a page of storage with the value and a marker indicating that the page marks an end of storage that has been allocated for the tier of user data storage may be identified. Storage may be allocated from a page immediately preceding the identified page.

Identifying allocated blocks in a storage system

A method is used for efficient storage allocation in a storage system. An infrastructure manager receives a request for storage from a first storage operating entity. The infrastructure manager identifies, from entries in a pagebin, a pagelist with sufficient available storage to satisfy the request. The infrastructure manager locks the pagebin while assigning the identified pagelist to the first storage operating entity. Upon a commitment of the identified pagelist by the first storage operating entity, the infrastructure manager unlocks the pagebin and identifies, from the entries in the pagebin, a second pagelist with sufficient available storage to satisfy a request from a second storage operating entity.

Method and system for efficient allocation of storage

A method, system, and computer program product for encoded virtual block deferred reference counting comprising receiving an input/output ('IO') request for data, the data associated with a virtual block, updating a reference count structure to reflect the IO request, and updating, out of line from the IO request, one or more reference counts associated with the virtual block to reflect the result of the IO request based on the updated reference count structure.

Technique for encoding deferred reference count increments and decrements

A method, system, and computer program product for multi-generational virtual block compaction comprising identifying a first virtual block, the first virtual block being associated with a first generation number, determining a second virtual block as an appropriate target for live information in the first virtual block, creating an association between the second virtual block and the first virtual block, updating the live information in the first virtual block to be associated with the second virtual block, updating a generation information mapping associated with the first virtual block; and associating a second generation number with the first virtual block.

Multi-generational virtual block compaction

A logical unit of non-volatile data storage is provided for persistently storing metadata. The logical unit is provided by allocating RAID (Redundant Array of Independent Disks) extents to the logical unit, and allocating logical block addresses for the logical unit from within a logical address space of the logical unit to store blocks of metadata written to the logical unit. In response to detecting that a stored indication of a last allocated logical block address for the logical unit has been lost, two RAID extents that were last allocated to the logical unit are identified, and a binary search is performed across logical block addresses within the two RAID extents that were last allocated to the logical unit to locate the last allocated logical block address for the logical unit within the logical address space of the logical unit.

Recovery of last allocated logical block address

A method, computer program product, and computing system for processing higher-level metadata portions to identify each occurrence of a pointer to a lower-level metadata portion; and generating a pointer record within a memory device that memorializes each occurrence of a pointer to a lower-level metadata portion and identifies a specific lower-level metadata portion to which the pointer is pointing, thus resulting in a plurality of pointer records.

File system check system and method

A method, computer program product, and computer system for forming, by a computing device, one or more virtual storage arrays using one or more storage processor virtual machines. A storage stack may be run inside the one or more storage processor virtual machines. One or more storage device drives of the one or more virtual storage arrays may be simulated as files.

Growing community of inventors

Shrewsbury, MA, United States of America

Ashok Tamilarasan