Honeycombdata Inc.

Honeycombdata (Nantong) Limited

Xiangyong Ouyang

Sushma Devendrappa

Jongman Yoon

Yu Zhang

Haibo Wu

Yunxiang Zhang

Yilun Chen

Meng Wang

The present disclosure relates to a data storage device and a storage control method based on a log-structured merge tree. The log-structured merge tree comprises a plurality of SST files stored on at least one storage medium. The storage control method comprises: using a first filter to obtain the SST file set matched by the query key; using a second filter to globally sort the matching tags in the SST file set to generate a global tag set; the global tag set selects SST files to perform file IO operations to read key-value pairs. The storage control method selects the SST file to perform file IO operations according to the global tag set, thereby reducing the number of file IO operations in data reading operations, further improving file IO efficiency.

Data storage device and storage control method based on log-structured merge tree

A storage device, such as a NAND flash device, includes a controller that assigns host read commands to a high priority queue and all other I/O commands including host write commands to a low priority queue. The controller executes any commands in the high priority queue before executing commands in the low priority queue. Block write commands are broken into page write commands that are added to the low priority queue, thereby enabling any host read commands to be interleaved with execution of the page write commands, rather than waiting for completion of a block write command. Coherency between overlapping commands is performed by a host device coupled to the controller such that no checking of coherency is performed by the SSD controller.

Reducing read command latency in storage devices

A storage device, such as a NAND flash device, avoids the need for garbage collection. An application executing on a host system tracks data objects that are marked as invalid and maintains an association between data objects and logical blocks, each logical block corresponding to a physical block of memory in the NAND flash device. Upon determining that the logical block contains no valid objects, the application instructs an SSD to trim the physical block of memory corresponding to the logical block. The application also aggregates write commands until a full block of data is ready to be written, at which point the application transmits a write command to the SSD.

Eliminating garbage collection in nand flash devices

A storage device, such as a NAND flash device, includes a controller that maintains a temperature for a plurality of data blocks, the temperature calculated according to a function that increases with a number of valid data objects in the block and recency with which the valid data objects have been accessed. Blocks with the lowest temperature are selected for garbage collection. Recency for a block is determined based on a number of valid data objects stored in the block that are referenced in a hot list of a LRU list. During garbage collection, data objects that are least recently used are invalidated to reduce write amplification.

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South San Francisco, CA, United States of America

Xiangyong Ouyang