System and method for dynamically changing the power mode of storage disks based on redundancy and system load

• US 7,516,346 B2
• Filed: 10/25/2005
• Issued: 04/07/2009
• Est. Priority Date: 10/28/2004
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Laboratories America Inc (NEC Corporation)
• Inventors: Pinheiro, Eduardo, Bianchini, Ricardo, Dubnicki, Cezary
• Primary Examiner(s): Lee; Thomas
• Assistant Examiner(s): Abbaszadeh; Jaweed A
• Application Number:
  US11/163,607
• Publication Number:
  US 20060107099A1
• Time in Patent Office: 1,260 Days
• Field of Search: 713/300, 713/320, 713/324
• US Class Current: 713/324
• CPC Class Codes: G06F 1/3221 of disk drive devices
• CPC Class Codes: G06F 1/3268 Power saving in hard disk drive
• CPC Class Codes: G06F 3/0625 Power saving in storage systems
• CPC Class Codes: G06F 3/0634 by changing the state or mode of one or more devices
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A system and method for reducing energy consumption in an information storage system is disclosed which takes advantage of the redundancy in a typical storage system.

Claims

1. A method of reducing power consumption in a redundant storage system, comprising:

diverting read requests to a first subset of storage disks in the redundant storage system, so that a second subset of remaining storage disks in the redundant storage system can transition to a lower power mode until the second subset of remaining storage disks is needed to satisfy a write request, wherein all of the storage disks in the redundant storage system are dynamically assigned between the first and second subsets based on redundancy requirements and system load in the redundant storage system;

detecting if the system load in the redundant storage system is high; and

if the system load is high, adding one or more storage disks from the second subset of remaining storage disks to the first subset of storage disks in the redundant storage system so as to handle the system load;

detecting if the system load in the redundant storage system is low; and

if the system load is low, adding one or more storage disks from the first subset of storage disks to the second subset of remaining storage disks in the redundant storage system.

2. The method of claim 1 further comprising buffering write requests to the second subset of remaining storage disks so as to minimize a number of transitions from the lower power mode to a higher power mode needed to handle the write requests.

3. The method of claim 1 wherein the redundant storage system has (n, m) redundancy and wherein D storage disks are assigned to the first subset of storage disks and wherein D·

(n/m) storage disks are assigned to the second subset of storage disks in the redundant storage system.

4. The method of claim 1 wherein each storage disk is a storage resource on a single machine.

5. The method of claim 1 wherein each storage disk is a storage resource in a distributed system.

6. The method of claim 1, further comprising:

in response to a write request, writing data to the second subset of remaining storage disks in the redundant storage system without writing the data to the first subset of storage disks in the redundant storage system.

7. A redundant storage system comprising:

a plurality of storage disks divided into a first subset, wherein all of the plurality of storage disks are dynamically assigned between the first and second subset based on redundancy requirements and system load;

a module which diverts read requests to the first subset of storage disks in the redundant storage system, so that the second subset of storage disks in the redundant storage system can transition to a lower power mode until a second subset of storage disks is needed to satisfy a write request;

a detection module which detects if the system load in the redundant storage system is high and detects if the system load in the redundant storage system is low; and

a module which, if the system load is high, adds one or more storage disks from the second subset to the first subset of storage disks in the redundant storage system so as to handle the system load and if the system load is low, adds one or more storage disks from the first subset to the second subset.

8. The redundant storage system of claim 7 further comprising a buffer for buffering write requests to the second subset of remaining storage disks so as to minimize a number of transitions from the lower power mode to a higher power mode needed to handle the write requests.

9. The redundant storage system of claim 7 wherein the redundant storage system has (n, m) redundancy and wherein D storage disks are assigned to the first subset of storage disks and wherein D·

(n/m) storage disks are assigned to the second subset of storage disks in the redundant storage system.

10. The redundant storage system of claim 7 wherein each storage disk is a storage resource on a single machine.

11. The redundant storage system of claim 7 wherein each storage disk is a storage resource in a distributed system.

12. A computer-implemented method of reducing power consumption in a redundant storage system, comprising:

diverting read requests to a first subset of storage disks in the redundant storage system, so that a second subset of remaining storage disks in the redundant storage system can transition to a lower power mode until the second subset of remaining storage disks is needed to satisfy a write request, wherein all of the storage disks in the redundant storage system are dynamically assigned between the first and second subsets based on redundancy requirements and system load in the redundant storage system; and

buffering write requests to the second subset of remaining storage disks so as to minimize a number of transitions from the lower power mode to a higher power mode needed to handle the write requests.