Western Digital Technologies, Inc.

David George Dreyer

Colin Christopher McCambridge

Adam Michael Espeseth

Sanjay Subbarao

Dylan Mark Dewitt

Phillip Peterson

Steven Theodore Sprouse

James M Higgins

Kevin James Wendzel

Rodney Brittner

Mark David Myran

Alex Robert Gronseth

Techniques for improved copy on write functionality within an SSD are disclosed. In some embodiments, the techniques may be realized as a method for providing improved copy on write functionality within an SSD including providing, in memory of a device, an indirection data structure. The data structure may include a master entry for cloned data, the master entry having a reference to one or more indexes and a clone entry for the cloned data, the cloned entry having at least one of: a reference to a master index, a reference to a next index, and a value indicating an end of a data structure. The techniques may include traversing, using a computer processor, one or more copies of the cloned data using one or more of the references.

System and method for copy on write on an SSD

A method of indirection replay for a flash storage system includes writing data, in a host stream, to blocksets of the flash storage system. The host blocksets are assigned a major sequence number incremented from the most recently closed host blockset. The method includes writing an indirection journal to each host blockset which are associated with the assigned major sequence number. The method includes writing data, in a garbage collection (GC) stream, to other blocksets of the flash storage system. The GC blocksets are assigned a major sequence number, based on the most recently closed host blockset, and a minor sequence number, incremented from the most recently closed GC blockset. The method includes writing an indirection journal to each GC blockset which are associated with the assigned major and minor sequence numbers. The indirection table is constructed by replaying the journals of the blocksets in order of major sequence and minor sequence numbers.

Multi-stream journaled replay

The present disclosure generally relates to solid state storage device and techniques for conserving storage capacity associated therewith. Several embodiments are presented, including a data storage device, data storage controller, and methods for using the same are provided in the subject disclosure. A data storage device includes: a plurality of memory devices, a controller coupled to the plurality of memory devices and configured to program data to and read data from the plurality of memory devices, a memory including a logical-to-physical address translation map configured to enable the controller to determine a physical location of stored data in the plurality of memory devices, where the logical-to-physical address translation map contains at least one entry that merges at least two addresses that map, respectively, to at least two physical locations in the plurality of memory devices, where the controller is configured to encode each merged entry with an error-correcting code.

Scaling large drives using enhanced DRAM ECC

The present disclosure generally relates to a method and system for efficiently sharing limited memory among multiple processors. Each processor has a local linked list. The local linked list identifies the pages allocated to the specific processor as well as the number of free codewords for each allocated page. Additionally, the local linked list includes the location of the next free codeword(s) for each allocated page. When all codewords are available, the page is considered free and may be sent back to the page pool used by all of the processors. If there are a sufficient number of contiguous free codewords on an allocated page, then new codeword data may be stored in the page. If there is not a sufficient number of contiguous free codewords on any allocated page, then a new page is allocated from the page pool. Thus, efficient allocate of memory resources is achieved.

Allocating shared memory among multiple tasks in a multiprocessor environment

An apparatus for implementing an enhanced-write-bandwidth caching stream includes a memory that stores machine instructions and a processor that executes the machine instructions. The apparatus apportions a first address space and a second address space that comprises a logical namespace. The apparatus also subjects the first address space to host-write throttling, and exempts the second address space from host-write throttling. The apparatus further requires that valid data in memory cells corresponding to the second address space be invalidated at an interval not to exceed a number of host writes equaling the capacity of the second address space.

Method for providing nonvolatile storage write bandwidth using a caching namespace

An apparatus for implementing an enhanced-write-bandwidth caching stream includes a memory that stores machine instructions and a processor that executes the machine instructions. The apparatus receives a first host write stream and a second host write stream that comprises latency-sensitive host write requests. The apparatus also subjects the first host write stream to host-write throttling, and exempts the second host write stream from host-write throttling. The apparatus further requires that the second host write stream invalidate logical blocks in an order corresponding to a previous order in which the respective logical blocks were previously programmed.

In general, techniques are described for stream management in storage devices. A storage device comprising a memory device and a processor may be configured to perform the techniques. The processor may detect a stream collision in which a host device writes a first version of a logical block (LB) to a first stream, and writes a second version of the same LB to a second stream. The processors may compare a first blockset sequence number (BSN) associated with a first collection of physical blocks referenced by the first stream to a second BSN associated with a second collection of physical blocks referenced by the second stream. Based on the comparison of the first BSN to the second BSN, the processor may write, to the mem device, the second version of the LB to the first stream.

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Rochester, MN, United States of America

David George Dreyer