Using flash storage devices with different sized erase blocks

• US 10,496,330 B1
• Filed: 10/31/2017
• Issued: 12/03/2019
• Est. Priority Date: 10/31/2017
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Pure Storage, Inc.
• Inventors: Bernat, Andrew R., Brennan, Timothy W., McAuliffe, Mark L., Seppanen, Eric D., Vachharajani, Neil Buda
• Primary Examiner(s): Khan, Masud K
• Application Number:
  US15/799,950
• Time in Patent Office: 763 Days
• CPC Class Codes: G06F 11/1004 to protect a block of data words, e.g. CRC or checksum G06F11/1076 takes precedence; security arrangements for protecting computers or computer systems against unauthorized activity G06F21/00
• CPC Class Codes: G06F 11/108 Parity data distribution in semiconductor storages, e.g. in SSD
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0253 Garbage collection, i.e. reclamation of unreferenced memory
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G06F 2212/7206 Reconfiguration of flash memory system
• CPC Class Codes: G06F 2212/7208 Multiple device management, e.g. distributing data over multiple flash devices
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays
• CPC Class Codes: G11C 16/16 for erasing blocks, e.g. arrays, words, groups

Abstract

A method of using flash storage devices with different sized erase blocks is provided. The method includes allocating a plurality of erase blocks of heterogeneous erase block sizes to a RAID stripe, to form a tile pattern having the heterogeneous erase block sizes in the RAID stripe. The method includes writing the RAID stripe across the flash storage devices in accordance with the allocating, and stopping the writing the RAID stripe, responsive to contents of the RAID stripe reaching a threshold.

Claims

1. A method of using flash storage devices with different sized erase blocks, comprising:

allocating a plurality of erase blocks of heterogeneous erase block sizes to a RAID stripe, to form a tile pattern having the heterogeneous erase block sizes in the RAID stripe, the tile pattern comprising a plurality of columns of the RAID stripe, each column having erase blocks from a same one of a plurality of flash storage devices, and differing columns having erase blocks from differing ones of the plurality of flash storage devices;

writing the RAID stripe across the flash storage devices in accordance with the allocating; and

stopping the writing the RAID stripe, responsive to contents of the RAID stripe reaching a threshold.

2. The method of claim 1, further comprising:

re-allocating one or more remaining unwritten portions of the plurality of erase blocks to a further RAID stripe.

3. The method of claim 1, further comprising:

writing metadata in the RAID stripe at predefined offsets so that each of the plurality of erase blocks begins with a metadata section.

4. The method of claim 1, further comprising:

performing garbage collection in the flash storage devices, with the RAID stripe as a single element for the garbage collection.

5. The method of claim 1, further comprising:

performing garbage collection in the flash storage devices, to collect portions of erase blocks; and

erasing at least one of the plurality of erase blocks, responsive to determining all data in the at least one of the plurality of erase blocks is obsoleted.

6. The method of claim 1, wherein the allocating comprises:

combining a plurality of erase blocks of smaller erase block sizes to form one or more block units each having a combined block size greater than or equal to another of the plurality of erase blocks.

7. The method of claim 1, wherein the plurality of flash storage devices are distributed across multiple chassis.

8. A tangible, non-transitory, computer-readable media having instructions thereupon which, when executed by a processor, cause the processor to perform a method comprising:

defining a RAID stripe having a tile pattern of a plurality of erase blocks with heterogeneous erase block sizes from flash memory storage devices, the tile pattern comprising a plurality of columns of the RAID stripe, each column having erase blocks from a same one of a plurality of flash memory storage devices, and differing columns having erase blocks from differing ones of the plurality of flash memory storage devices;

writing to the RAID stripe, across the flash memory storage devices; and

ceasing the writing the RAID stripe, as full, when one or more of the plurality of erase blocks is full or RAID stripe contents reaches a threshold.

9. The computer-readable media of claim 8, wherein the method further comprises:

assigning unused portions of the plurality of erase blocks to a further RAID stripe.

10. The computer-readable media of claim 8, wherein the method further comprises:

defining an offset, as a common divisor of the heterogeneous erase block sizes; and

writing metadata in the RAID stripe at intervals of the offset, to begin each of the plurality of erase blocks with a metadata section.

11. The computer-readable media of claim 8, wherein the method further comprises:

defining the RAID stripe as a single element for garbage collection.

12. The computer-readable media of claim 8, wherein the method further comprises:

forming a combined block from two or more of the plurality of erase blocks, of smaller erase block sizes, to have a combined block size greater than or equal to a further one of the plurality of erase blocks.

13. The computer-readable media of claim 8, wherein the plurality of flash memory storage devices are distributed across multiple chassis.

14. A storage system, comprising:

a plurality of flash storage devices having heterogeneous erase block sizes; and

at least one processor, configurable to;

assign erase blocks to one or more RAID stripes, including a RAID stripe having a tile pattern with heterogeneous erase block sizes, the tile pattern comprising a plurality of columns of the RAID stripe, each column having erase blocks from a same one of a plurality of flash storage devices, and differing columns having erase blocks from differing ones of the plurality of flash storage devices; and

write data to the RAID stripe having the heterogeneous erase block sizes, to fill the RAID stripe until contents of the RAID stripe reaches a threshold.

15. The storage system of claim 14, wherein the at least one processor is further configurable to:

assign unused portions of the erase blocks of the RAID stripe to a further RAID stripe.

16. The storage system of claim 14, wherein the at least one processor is further configurable to:

write, at predefined offsets, metadata to the RAID stripe having the heterogeneous erase block sizes, to begin each of the erase blocks in the RAID stripe with a metadata section.

17. The storage system of claim 14, wherein the at least one processor is further configurable to:

performing garbage collection in the plurality of flash storage devices, using the RAID stripe having the heterogeneous erase block sizes as a single element.

18. The storage system of claim 14, wherein the at least one processor is further configurable to:

perform garbage collection in the plurality of flash storage devices, to collect portions of erase blocks and to erase and reclaim one or more of the plurality of erase blocks having obsoleted data.

19. The storage system of claim 14, wherein the at least one processor is further configurable to:

form a block unit having a combined block size greater than or equal to erase block size of one of the plurality of erase blocks, from two or more erase blocks of smaller erase block sizes.

20. The storage system of claim 14, wherein the plurality of flash storage devices are distributed across multiple chassis.