Method of managing a data storage array, and a computer system including a raid controller

• US 7,337,269 B2
• Filed: 10/03/2002
• Issued: 02/26/2008
• Est. Priority Date: 10/03/2002
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Umberger, David, Navarro, Guillermo
• Primary Examiner(s): Kim; Hong
• Assistant Examiner(s): Rojas; Midys
• Application Number:
  US10/264,573
• Publication Number:
  US 20040068609A1
• Time in Patent Office: 1,972 Days
• Field of Search: 711/114, 711/112
• US Class Current: 711/112
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A method of managing disk array includes providing a disk array and a RAID controller, receiving commands using the controller, accessing data within the array responsive to the commands, determining the amount of free space within the disk array, measuring a rate of data access; and selectively creating free space within the disk array responsive to the determining and the measuring. A computer disk system includes an array of computer disks, a RAID controller respectively coupled to the array and configured to access data within the array and to determine the amount of free space within the array, and a user interface coupled to the controller, wherein the controller is further configured to measure a rate at which the array is accessed and to selectively create free space within the array responsive to the determining and the measuring.

Claims

1. A method of managing a RAID storage array, comprising:

providing a RAID disk array having a RAID controller;

receiving a plurality of commands from a user using the controller;

accessing data within the disk array responsive to the plurality of commands using the controller;

determining the amount of free space within the disk array using the controller;

measuring a utilization rate of the accessing using the controller; and

creating free space within the disk array, if the utilization rate is below a threshold utilization rate, responsive to the amount of free space, wherein the free space is not created if the utilization rate is greater than or equal to the threshold utilization rate whereby slowed response times that could occur under conditions of high utilization are avoided.

2. The method of claim 1, wherein the accessing comprises selectively storing data in and retrieving data from the array responsive to corresponding ones of the plurality of commands.

3. The method of claim 1, wherein the creating free space comprises selectively moving blocks of data within the disk array using the controller.

4. The method of claim 3, wherein the moving blocks of data comprises moving at least some blocks of data from a higher RAID level to a lower RAID level.

5. The method of claim 3, wherein at least a portion of the accessing and at least a portion of the creating free space occur at the same time.

6. A computer data storage system, comprising:

a plurality of computer disks configured as an array; and

a RAID controller respectively coupled to each of the computer disks within the array and configured to access data within the array and to determine the amount of free space within the array, wherein the controller is further configured to measure a utilization rate at which the array is accessed and to create free space within the array, if the utilization rate is below a threshold utilization rate, responsive to the free space, wherein the controller is further configured to create the free apace by selectively moving blocks of data to different RAID levels within the array, wherein the controller is further configured to access data within the array simultaneous with at least a portion of the creating free space, and wherein the free space is not created if the utilization rate is greater than or equal to the threshold utilization rate whereby slowed response times that could occur under conditions of high utilization are avoided.

7. The system in accordance with claim 6, wherein the controller is further configured to create the free space responsive to the determining and the measuring.

8. The system in accordance with claim 6, wherein the controller is further configured to create the free space responsive to the determining and the measuring and at least one pre-defined parameter.

9. The system in accordance with claim 6, wherein the controller is further configured to perform the determining and the measuring from time to time.

10. A computer data system, comprising:

RAID storage means for storing data;

means for determining a quantity of free space within the RAID storage means;

means for reading and writing data within the RAID storage means responsive to respective commands;

means for measuring a utilization rate of the reading and writing the data; and

means for selectively moving the data within the RAID storage means responsive to the quantity determined by the determining means and the rate measured by the measuring means, such that free space is created within the RAID storage means, but wherein the data is not moved if the utilization rate is greater than or equal to a threshold utilization rate.

11. The system in accordance with claim 10, wherein the means for selectively moving includes a controller configured determine the quantity of free space end to measure the rate of the reading and writing the data and to selectively move the data responsive to the determining and the measuring.

12. The system in accordance with claim 11, wherein the controller is further configured selectively move the data responsive to utilization rate in a manner that reduces the impact of data movement on performance.

13. The system in accordance with claim 11, wherein the controller is further configured to perform the determining and the measuring and the selectively moving the data from time to time.

14. The system in accordance with claim 11, wherein the controller is further configured to selectively move the data in accordance with the functions Uth(F)=exp(−

α

F²) and α

=[1/Fth²] In(Umin), wherein Uth(F) is a threshold value for comparison with the measured rate, F is the determined quantity of free space within the RAID storage means, Fth is a pre-defined minimum quantity of free space to be maintained within the RAID storage means, and Umin is a pre-defined minimum value for Uth(F).

15. The system in accordance with claim 10, wherein the means for selectively moving includes means for selectively moving the data between different RAID levels within the RAID storage means.

16. The system in accordance with claim 10, wherein the means for reading and writing the data and the means for selectively moving are configured such that at least of portion of the reading and writing the data occurs simultaneously with the creating free space.

17. A data storage system, comprising:

a plurality of data storage elements configured as an array;

a RAID controller respectively coupled to each of the storage elements within the array and configured to selectively read data from and write data to the array and to determine the amount of free space within the array; and

a user interface coupled to the controller and configured to selectively issue a plurality of different commands respectively reading data from and writing data to the array by way of the controller, wherein the controller is further configured to measure a utilization rate at which the data is read from and written to the array by way of the user interface, and wherein the controller is further configured to create free space within the array from time to time responsive to the determining and the measuring, and wherein the creating the free space includes selectively moving blocks of data to different RAID levels within the array, and wherein the controller is further configured to read data from and write data to the array responsive to commands received by way of the user interface simultaneously with at least a portion of the creating the free space, the controller being configured to move the data in accordance with the functions Uth(F)=exp(−

α

F²) and α

=[1/Fth²] In(Umin), wherein Uth(F) is a threshold value for comparison with the measured rate, F is the determined quantity of free space within the array, Fth is a pre-defined minimum quantity of free space to be maintained within the array, and Umin is a pre-defined minimum value for Uth(F), wherein the data is not moved if the utilization rate is greater than or equal to Uth(F).