Emc IP Holding Company LLC

Haleh Tabrizi

Seungjune Jeon

Andrew Cullen

Jeffrey S Bonwick

Michael W Shapiro

Rajiv Agarwal

Jeffrey Paul Ferreira

Justin L Ha

Alan Hanson

Michael Rijo

Samuel Hudson

In general, embodiments of the technology relate to a method for characterizing persistent storage. The method includes selecting a sample set of physical addresses in a solid state memory module, where the sample set of physical addresses is associated with a region in the solid state memory module (SSMM). The method further includes issuing a write request to the sample set of physical addresses, after issuing the write request, issuing a request read to the sample set of physical addresses to obtain a copy of the data stored in the sample set of physical addresses, obtaining an error parameter for the copy of the data, determining a calculated P/E cycle value for the SSMM using at least the error parameter; and storing the calculated P/E cycle value in the SSMM.

Method and system for offline program/erase count estimation

In general, embodiments of the technology relate to a method for adjusting solid state memory write parameters. The method includes obtaining a performance goal for the solid state memory, receiving a client write request for data from a client, where the client write request comprises a logical address and data to be written. The method further includes determining a physical address corresponding to the logical address, where the physical address comprises a page number for a physical page in the persistent storage, obtaining at least one verify threshold value using the performance goal, issuing a control module program request including the data to be written and the at least one verify threshold value to a storage module, where the storage module comprises the physical page, and programming the data into the physical page of the storage module using the at least one verify threshold value.

Method and system for adapting solid state memory write parameters to satisfy performance goals based on degree of read errors

A method for managing persistent storage. The method includes selecting a page for a proactive read request, where the page is located in the persistent storage. The method further includes issuing the proactive read request to the page, receiving, in response to the proactive read request, a bit error value (BEV) for data stored on the page, obtaining a BEV threshold (T) for the page, wherein T is determined using a program/erase cycle value associated with the page and a retention time of the data stored on the page, making a first determination that the BEV is greater than T, based on the first determination: identifying an m-page, where the m-page is a set of pages and the page is in the set of pages, and setting the m-page as non-allocatable for future operations.

Method and system for improving flash storage utilization by predicting bad M-pages

In general, the technology relates to a method for managing persistent storage. The method includes selecting a sample set of physical addresses in a solid state memory module, and performing a garbage collection operation on the sample set of physical addresses. The method further includes, after the garbage collection operation, issuing a write request to the sample set of physical addresses, issuing a request read to the sample set of physical addresses to obtain a copy of the data stored in the sample set of physical addresses, determining an error rate in the copy of the data stored using an Error Correction Code codeword or known data in the write request, determining a calculated P/E cycle value for the SSMM using at least the error rate, and updating an in-memory data structure in a control module with the calculated P/E cycle value.

Method and system for online program/erase count estimation

In general, embodiments of the technology relate to improving read performance of solid-state storage by using decoding parameters deemed particularly suitable for the read operation that is currently being performed. More specifically, embodiments of the technology relate to using different decoding parameters when a read operation needs to be repeated because the initial read operation has failed.

Method and system for systematic read retry flow in solid state memory using a retry table

A system and method for storing data including receiving a request to write data and in response to the request selecting a set of free physical locations in persistent storage. The system and method further include determining an aggregate failure rate of the set of free physical locations, making a first determination that the aggregate failure rate is less than a failure rate threshold for the persistent storage and based on the first determination calculating a parity value using at least a portion of the data, and writing the data and the parity value to the set of free physical locations.

Method and system for checkerboard RAID

A method for reading data from persistent storage. The method includes receiving a client read request for data from a client. The client read request includes a logical address. The method further includes determining a physical address corresponding to the logical address, determining that the physical address is directed to an open block in the persistent storage and determining that the physical address is directed to a last closed word line of the open block. The method further includes, based on these determinations, obtaining at least one read threshold value for the reading from last closed word lines, issuing a control module read request comprising the at least one read threshold value to a storage module that includes the open block, and obtaining the data from the open block using the at least one read threshold value.

Method and system for improving flash storage read performance in partially programmed blocks

Method and system for systematic read retry flow in solid state memory

A method for managing a storage appliance. The method includes determining an input/output (I/O) workload characterization (IWC) for the storage appliance. The method further includes determining an optimized temperature for the storage modules in the storage appliance based on the IWC, determining that a current temperature of the storage modules is not the optimized temperature, and modifying operation of at least one active cooling component in the storage appliance to change the current temperature of the storage modules to the optimized temperature.

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San Francisco, CA, United States of America

Haleh Tabrizi