PRIORITY COMMAND QUEUES FOR LOW LATENCY SOLID STATE DRIVES

• US 20100082879A1
• Filed: 09/26/2008
• Published: 04/01/2010
• Est. Priority Date: 09/26/2008
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Pinson, Jeremy Michael, MCKEAN, BRIAN D., Kidney, Kevin Lee
• Granted Patent: US 8,756,369 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0658 Controller construction arrangements
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A method, apparatus, and system of a priority command queues for low latency solid state drives are disclosed. In one embodiment, a system of a storage system includes a command sorter to determine a target storage device for at least one of a solid state drive (SSD) command and a hard disk drive (HDD) command and to place the command in a SSD ready queue if the SSD command is targeted to a SSD storage device of the storage system and to place the HDD command to a HDD ready queue if the HDD command is targeted to an HDD storage device of the storage system, a SSD ready queue to queue the SSD command targeted to the SSD storage device, and a HDD ready queue to queue the HDD command targeted to the HDD storage device.

Claims

1. A system of a storage system comprising:

a command sorter to determine a target storage device for at least one of a solid state drive (SSD) command and a hard disk drive (HDD) command and to place the command in a SSD ready queue if the SSD command is targeted to a SSD storage device of the storage system and to place the HDD command to a HDD ready queue if the HDD command is targeted to an HDD storage device of the storage system;

a SSD ready queue to queue the SSD command targeted to the SSD storage device; and

a HDD ready queue to queue the HDD command targeted to the HDD storage device.

2. The system of claim 1 further comprising a command scheduler to determine an availability level of at least one of a SSD process queue and a HDD process queue and to communicate at least one of the SSD command from at least one of the SSD ready queue and the HDD command from the HDD ready queue to a command processor according to the availability level.

3. The system of claim 2 wherein the command processor communicates the command to at least one of the SSD process queue and the HDD process queue according to a scheduling instruction from the command scheduler.

4. The system of claim 3:

wherein the SSD storage device is a non-volatile computer memory that is electrically erasable and reprogrammable;

wherein the command sorter uses at least one of a hash table and a data mapping table to determine whether a command type; and

wherein the storage system is a system that shares and replicates data using at least one HDD disk drive and at least one SSD storage device.

5. The system of claim 4:

wherein there are a plurality of SSD storage devices and a plurality of HDD storage devices;

wherein there is a single SSD ready queue for the storage system;

wherein there is a single HDD ready queue for the storage system;

wherein each SSD storage device has a unique SSD process queue; and

wherein each HDD storage device has a unique HDD process queue.

6. The system of claim 4:

wherein the SSD storage device uses a NAND flash architecture;

wherein storage is a redundant array of independent disks (RAID) system having both a plurality of HDD disk drives and a plurality of SSD storage devices; and

wherein the SSD storage device and the HDD storage device are peer storage subsystems of the RAID system.

7. The system of claim 4:

further comprising spun down HDD ready queue to queue an other HDD command targeted to a spun down HDD storage device;

wherein the command sorter further determines that a spun down HDD command is targeted to a spun down HDD storage device;

wherein the command sorter places the spun down HDD command in a spun down HDD ready queue; and

wherein the command processor places the spun down HDD command in a spun down HDD process queue.

8. The system of claim 7 further comprising a computer readable medium having computer executable instructions adapted to perform the system of claim 1.

9. A method of a storage system comprising:

determining a target storage device of the storage system for a at least one of a solid state drive (SSD) command and a hard disk drive (HDD) command;

placing the SSD command in a SSD ready queue if the SSD command is targeted to a SSD storage device of the storage system; and

placing the HDD command in a HDD ready queue if the HDD command is targeted to an HDD storage device of the storage system.

10. The method of claim 9 further comprising:

determining a latency period of the SSD command;

determining an other latency period of the HDD command; and

proportionately allocating a set of storage system resources to service the SSD command in the SSD ready queue at a faster rate than the HDD command in the HDD ready queue according to the difference between the latency period of the SSD command and the other latency period of the HDD command.

11. The method of claim 10 further comprising:

determining an availability level of a SSD process queue;

determining an other availability level of a HDD process queue;

placing the SSD command located in the SSD ready queue in a command processor if the availability level of the SSD process queue is greater than the other availability level of the HDD process queue; and

placing the HDD command located in the HDD ready queue in the command processor if the other availability level of the HDD process queue is greater than the availability level of the SSD process queue.

12. The method of claim 9 wherein the storage system has a hybrid storage device that has both a SSD storage component and an HDD storage component.

13. The method of claim 9 further comprising:

determining an availability level of a SSD component process queue;

determining an other availability level of a HDD component process queue;

placing the SSD command located in the SSD component ready queue in a component command processor if the SSD component process queue has a greater availability level than the HDD component process queue; and

placing the HDD command located in the HDD component ready queue in the component command processor if the HDD component process queue has a greater availability level than the SSD component process queue.

14. The method of claim 9:

wherein the storage is a redundant array of independent disks (RAID) system having both a plurality of HDD disk drives and a plurality of SSD storage devices; and

wherein the SSD storage device and the HDD storage device are peer storage subsystems of the RAID system.

15. The method of claim 9 wherein the SSD storage device uses a NAND flash architecture as a computer memory.

16. A method comprising:

configuring a computer storage system with both a solid state drive (SSD) data storage device and a hard disk drive data storage device;

configuring a command sorter to determine if a command is assigned to at least one of the SSD data storage device and the HDD data storage device;

configuring the command sorter to place the command assigned to the SSD data storage device in a SSD ready queue; and

configuring the command sorter to place the command assigned to the HDD data storage device in an HDD ready queue.

17. The method of claim 16 further comprising:

determining an availability of a SSD process queue and an HDD process queue; and

configuring a command scheduler to take the command assigned to the SSD data storage device and place it in a command processor if the SSD process queue has a greater availability than the HDD process queue.

18. The method of claim 17 further comprising configuring the command scheduler to take the command assigned to the HDD data storage device and place it in the command processor if the HDD process queue has a greater availability than the SSD process queue.

19. The method of claim 17 further comprising:

configuring a computer storage device of the computer storage system with a hybrid data storage device that has both a SSD data sub-storage device and a HDD sub-storage device and wherein the hybrid data storage device is a peer device to the SSD data storage device and the HDD data storage device;

determining if the command is assigned to at least one of the SSD data sub-storage device and the HDD data sub-storage device;

placing the command assigned to the SSD data sub-storage device in a SSD ready sub-queue; and

placing the command assigned to the HDD data sub-storage device in an HDD ready sub-queue.

20. The method of claim 19 further comprising:

determining an availability of a SSD process sub-queue and an HDD process sub-queue;

configuring a command sub-scheduler to take the command assigned to the SSD data sub-storage device and place it in a command sub-processor if the SSD process sub-queue has a greater availability than the HDD process sub-queue; and

configuring the command sub-scheduler to take the command assigned to the HDD data sub-storage device and place it in the command sub-processor if the HDD process sub-queue has a greater availability than the SSD process sub-queue.