Apparatus and method for reallocating logical to physical disk devices using a storage controller, with access frequency and sequential access ratio calculations and display

• US 20020099908A1
• Filed: 04/02/2002
• Published: 07/25/2002
• Est. Priority Date: 04/08/1996
• Status: Active Grant

• Current Assignee: Akira Yamamoto, Takao Satoh, Yasutomo Yamamoto
• Original Assignee: Akira Yamamoto, Takao Satoh, Yasutomo Yamamoto
• Inventors: Yamamoto, Akira, Satoh, Takao, Yamamoto, Yasutomo
• Granted Patent: US 6,708,252 B2
• Time in Patent Office: Days
• US Class Current: 711/114
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/2005 using redundant communication controllers
• CPC Class Codes: G06F 11/2007 using redundant communication media
• CPC Class Codes: G06F 11/201 between storage system components
• CPC Class Codes: G06F 11/2087 with a common controller
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• CPC Class Codes: G06F 2211/1004 Adaptive RAID, i.e. RAID system adapts to changing circumstances, e.g. RAID1 becomes RAID5 as disks fill up
• CPC Class Codes: G06F 2211/104 Metadata, i.e. metadata associated with RAID systems with parity
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0646 Horizontal data movement in storage systems, i.e. moving data in between storage devices or systems
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0683 Plurality of storage devices
• CPC Class Codes: G06F 3/0685 : Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays
• CPC Class Codes: G06F 3/0689 : Disk arrays, e.g. RAID, JBOD

Abstract

A storage controller calculates an access frequency of each logical disk; that it selects a first logical disk device of which the access frequency exceeds a first predetermined value, the first logical disk device being allocated to a first physical disk device; selects a second logical disk device which has the access frequency equal to or less than a second predetermined value, the second d logical disk device being allocated to a second physical disk device; and reallocates the first and second logical device; and reallocates the first and second logical devices to the second and the first physical disk device, respectively.

Claims

1. A storage controller connecting one data processor unit to a plurality of physical disk devices for consecutively reallocating a plurality of logical disk devices as objects of accesses from the data processor unit respectively to the plural physical disk devices, comprising:

allocation means for allocating a logical disk device to at least one physical disk device such that the data is consecutively arranged in said at least one physical disk device;

collecting means for collecting access information for each of the logical disk devices; and

reallocation means for reallocating each of the logical disk devices to the physical disk devices in accordance with results from said collecting means.

2. A storage controller according to claim 1, further comprising:

display means for displaying the accepted access information on a service processor connected to the storage controller; and

reception means for receiving a reallocation instruction from an operator through the service processor.

3. A storage controller according to claim 1, further comprising:

reception means for receiving a reallocation instruction from the data processor unit.

4. A storage system comprising:

at least two physical disk devices storing data of a plurality of logical disk devices as objects of accesses from a data processor unit; and

a controller, connectable to the data processing unit, for controlling data accesses from the data processing unit,

wherein said controller performs the steps of;

detecting access activity to said logical disk devices in said at least two physical disk devices,

determining, in accordance with detected access activity, a first logical disk device in a first physical disk device having a first access activity and a second logical disk device in a second physical disk device having a second access activity, wherein said first access activity is greater than said second access activity, and

transferring data of said first logical disk device from said first physical disk device to said second physical disk device and transferring data of said second logical disk device from said second physical disk device to said first physical disk device,

wherein said first logical disk device is set to said second logical disk device and said second logical disk device is set to said first logical disk device.

5. A storage system according to claim 4, wherein said controller decides a logical disk device as said first logical disk if access activity to the logical disk device is greater than a predetermined first value of access activity.

6. A storage system according to claim 5, wherein said controller decides a logical disk device as said second logical disk if access activity to the logical disk device is greater than said predetermined second value of access activity.

7. A storage system according to claim 4, wherein said controller has a memory and transfers said first logical disk device and said data of said second logical disk device through said memory.

8. A storage system according to claim 4, wherein said controller has mapping information indicating positions of said logical disk devices in said physical disk devices.

9. A storage system according to claim 8, wherein said controller modifies said mapping information in accordance with a result of said transferring, and accesses data of said first logical disk device based on modified mapping information after said data of said first logical disk device is transferred to said second physical disk device.

10. A reallocating method, used in a storage system having a control unit connectable to a data processing unit, and a plurality of physical disk devices to which at least two logical disk devices are allocated, for reallocating said at least two logical disk devices to said plurality of physical devices, said method performed by said control unit comprising the steps of:

detecting access activity to said at least two logical disk devices;

determining, in accordance with detected access activity by said detecting step, a first logical disk device in a first physical disk device having a first value of access activity and a second logical disk device in a second physical disk device having a second value of access activity, where said first value of access activity is greater than said second value of access activity; and

swapping said first logical disk device and said second logical disk device so that data of said first logical disk device is transferred from said first physical disk device to said second physical disk device and data of said second logical disk device is transferred from said second physical disk device to said first physical disk device.

11. A reallocating method according to claim 10, further comprising the step of:

previously allocating data of said first logical disk device to said first physical disk device so that the data is consecutively arranged in said first physical disk device.

12. A reallocating method according to claim 10, wherein said swapping step comprising the steps of:

receiving an access request to an area of said first logical disk device from the data processing unit;

deciding, in response to said access request, whether or not the area of said first logical disk device has been swapped;

accessing to the first physical disk device if a result of said deciding step indicates that said area of said first logical disk device has not been swapped; and

accessing to said second physical disk device if the result of said deciding step indicates that said area of said first logical disk device has been swapped.

13. A storage system comprising:

at least two physical disk devices storing data of a plurality of logical disk devices as objects of accesses from a data processor unit; and

a controller, connectable to the data processing unit, for controlling data accesses from the data processing unit,

wherein said controller performs the steps of;

detecting access activities to said logical disk devices in said at least two physical disk devices,

determining, in accordance with detected access activities, a first logical disk device in a first physical disk device and a second logical disk device in a second physical disk device, where access activities to said first logical disk device is greater than access activities to said second logical disk device, and

swapping said first logical device and said second logical disk device so that said first logical disk device is allocated to said second physical disk device and said second logical disk device is allocated to said first physical disk device.