Single-level cell and multi-level cell hybrid solid state drive

• US 9,146,851 B2
• Filed: 03/26/2012
• Issued: 09/29/2015
• Est. Priority Date: 03/26/2012
• Status: Active Grant

• Current Assignee: Dell International LLC (Dell Technologies Inc.)
• Original Assignee: Compellent Technologies Incorporated (Dell Technologies Inc.)
• Inventors: Pittelko, Michael H.
• Primary Examiner(s): Tseng, Cheng-Yuan
• Assistant Examiner(s): Dewan, Kamal K
• Application Number:
  US13/429,511
• Publication Number:
  US 20130254458A1
• Time in Patent Office: 1,282 Days
• Field of Search: 711/103, 711/114, 711/154, 365/200, 714/704
• US Class Current: 1/1
• CPC Class Codes: G06F 12/02 Addressing or allocation; Relocation program address sequencing G06F9/00; arrangements for selecting an address in a digital store G11C8/00
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control

Abstract

A solid state drive (SSD) having a first memory portion comprising SLC flash memory and a second memory portion comprising MLC flash memory. The first memory portion may store read/write data, and the second memory portion may store read-only or read-mostly data. In some instances, the second memory portion may store historical data. The present disclosure also relates to a method of data progression in a hybrid solid state drive having both single-level cell (SLC) flash memory and multi-level cell (MLC) flash memory. The method may include monitoring write operations to the SLC memory, determining whether the frequency of write operations to a particular portion of the SLC memory is below a determined threshold, and moving the data stored in the particular portion of the SLC memory to the MLC memory.

Claims

1. A data storage system comprising:

a hybrid solid state drive (SSD) having both a first memory portion comprising single-level cell (SLC) flash memory and a second memory portion comprising multi-level cell (MLC) flash memory;

wherein the first memory portion is either read/write optimized or read optimized and the second memory portion is the other of either read/write optimized or read optimized from the first memory portion;

wherein at least one of the memory portions is reconfigurable on demand between a read/write optimized memory portion and a read optimized memory portion; and

wherein data progression is used to move read/write data to the read/write optimized memory portion and read-only data to the read optimized memory portion.

2. The data storage system of claim 1, wherein the first memory portion comprises less than 50% of the overall memory of the solid state drive.

3. The data storage system of claim 2, wherein the first memory portion comprises between about 20% and 30% of the overall memory of the solid state drive.

4. The data storage system of claim 1, wherein the first memory portion stores read/write data.

5. The data storage system of claim 1, wherein the second memory portion stores read-mostly data.

6. The data storage system of claim 4, wherein the second memory portion stores read-mostly data.

7. The data storage system of claim 6, wherein the second memory portion stores historical data.

15. The data storage system of claim 1, wherein data progression is used to automatically move data between the read/write optimized memory portion and the read optimized memory portion.

16. The data storage system of claim 1, wherein read/write data is separately bundled for execution and read-only data is separately bundled for execution.

8. A data storage system comprising at least one hybrid solid state drive (SSD) comprising single-level cell (SLC) flash memory that is read/write optimized and multi-level cell (MLC) flash memory that is read optimized, wherein read-only data is moved to the read optimized MLC flash memory, and wherein at least one of the SLC flash memory and MLC flash memory is reconfigurable on demand between read/write optimized and read optimized.

9. The data storage system of claim 8, further comprising hard disk drives.

10. The data storage system of claim 8, further configured to monitor write operations to the SLC memory of the hybrid SSD, determine whether the frequency of write operations to a particular portion of the SLC memory is below a determined threshold, and move the data stored in the particular portion of the SLC memory to the MLC memory of the hybrid SSD.

11. The data storage system of claim 10, further comprising another type of storage device, and configured to move data stored in the MLC memory of the hybrid SSD to the other type of storage device.

12. The data storage system of claim 11, wherein the other type of storage device is a hard disk drive.

13. The data storage system of claim 8, further configured to store historical data in the MLC memory of the hybrid SSD.

14. A method of data progression in a hybrid solid state drive having both single-level cell (SLC) flash memory that is read/write optimized and multi-level cell (MLC) flash memory that is read optimized, the method comprising:

monitoring write operations to the SLC memory;

determining whether the frequency of write operations to a particular portion of the SLC memory is below a determined threshold; and

if it is determined that the frequency of write operations to the particular portion of the SLC memory is below the determined threshold, moving the data stored in the particular portion of the SLC memory to the MLC memory; and

reconfiguring at least one of the SLC memory and MLC memory on demand between read/write optimized and read optimized.