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 6,446,161 B1
• Filed: 06/17/1999
• Issued: 09/03/2002
• Est. Priority Date: 04/08/1996
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Akira, Satoh, Takao, Yamamoto, Yasutomo
• Primary Examiner(s): Bragdon, Reginald G.
• Application Number:
  US09/335,175
• Time in Patent Office: 1,174 Days
• Field of Search: 711/114, 711/165, 711/170, 711/167
• 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 logical disk device being allocated to a second physical disk device; and reallocates the first and second logical devices to the second and the first physical disk devices, respectively.

Claims

1. A reallocating method, for use with a storage control unit connecting one data processor unit to a plurality of physical disk devices, for reallocating each of plural logical disk devices as objects of accesses from a data processor unit to the plurality of physical disk devices, said method comprising the steps of:

allocating data of 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;

calculating an access frequency for each of the logical disk devices;

selecting, according to results of said calculating step, a first logical disk device which has an access frequency exceeding a first predetermined value and a second logical disk device which has an access frequency equal to or less than a second predetermined value and which is allocated to a second physical disk device having a speed higher than a speed of a first physical disk device to which the first physical disk device is allocated; and

reallocating the first logical disk device to the second physical disk device and the second logical disk device to the first physical disk device, by exchanging contents of the first physical disk device with contents of the second physical disk device.

2. A reallocating method according to claim 1, further comprising the steps of:

displaying the access frequency calculated from the calculating step on a service processor connected to the storage control unit; and

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

3. A reallocating method according to claim 1, further comprising the step of:

receiving a reallocation instruction from the data processor unit.

4. A reallocating method according to claim 1, further comprising the steps of:

in response to an access request to an area of the first logical disk device from the data processor unit during the reallocation, deciding whether or not the reallocation to the area is terminated from the first physical disk device to the second physical disk device;

accessing to the first physical disk device in response to a non-termination of reallocating to the second physical disk device; and

accessing to the second physical disk device in response to a termination of reallocating to the second physical disk device.

5. A reallocating method, for use with a storage control unit connecting one data processor unit to a plurality of physical disk devices, for reallocating each of plural logical disk devices as objects of accesses from a data processor unit to the plurality of physical disk devices, said method comprising the steps of:

allocating data of 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;

calculating a sequential access ratio for each of the logical disk devices;

selecting, according to results of said calculating step, a first logical disk device which has a sequential access ratio exceeding a first predetermined value and a second logical disk device which has a sequential access ratio equal to or less than a second predetermined value and which is allocated to a second physical disk device enabling a sequential access having a speed higher than a speed of a first physical disk device to which the first physical disk device is allocated; and

reallocating the first logical disk device to the second physical disk device and the second logical disk device to the first physical disk device, by exchanging contents of the first physical disk device with contents of the second physical disk device.

6. A reallocating method according to claim 5, further comprising the steps of:

displaying the calculated sequential access ratio on a service processor connected to the storage control unit; and

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

7. A reallocating method according to claim 5, further comprising the step of:

receiving a reallocation instruction from the data processor unit.

8. A reallocating method according to claim 5, further comprising the steps of:

in response to an access request to an area of the first logical disk device from the data processor unit during the reallocation, deciding whether or not the reallocation of the area from the first physical disk device to the second physical disk device is terminated;

accessing to the first physical disk device in response to a non-termination of reallocating to the second physical disk device; and

accessing to the second physical disk device in response to a termination of reallocating to the second physical disk device.

9. 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 data of 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;

calculation means for calculating an access frequency for each of the logical disk devices;

selection means, according to results from said calculation means, for selecting a first logical disk device which has an access frequency exceeding a first predetermined value and a second logical disk device which has an access frequency equal to or less than a second predetermined value and which is allocated to a second physical disk device having a speed higher than a speed of a first physical disk device to which the first physical disk device is allocated; and

reallocation means for reallocating the first logical disk device to the second physical disk device and the second logical disk device to the first physical disk device, by exchanging contents of the first physical disk device with contents of the second physical disk device.

10. 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 data of a logical diskdevice to at least one physical disk device such that the data is consecutively arranged in said at least one physical disk device;

calculation means for calculating a sequential access ratio for each of the logical disk devices;

selection means, according to results from said calculation means, for selecting a first logical disk device which has a sequential access ratio exceeding a first predetermined value and a second logical disk device which has a sequential access ratio equal to or less than a second predetermined value and which is allocated to a second physical disk device enabling a sequential access having a speed higher than a speed of a first physical disk device to which the first physical disk device is allocated; and

reallocating the first logical disk device to the second physical disk device and the second logical disk device to the first physical disk device, by exchanging contents of the first physical disk device with contents of the second physical disk device.

11. A reallocating method, for use with a storage control unit connecting one data processor unit to a plurality of physical disk devices, for reallocating each of plural logical disk devices as objects of accesses from a data processor unit to the plurality of physical disk devices, said method comprising the steps of:

allocating data of 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;

calculating an access frequency for each of the logical disk devices;

selecting, according to results of said calculating step, a logical disk device which has an access frequency exceeding a first predetermined value and a second physical disk device which has a speed higher than a speed of a first physical disk device to which the logical disk device is allocated; and

reallocating contents of the logical disk device to the second physical disk device.

12. A reallocating method, for use with a storage control unit connecting one data processor unit to a plurality of physical disk devices, for reallocating each of plural logical disk devices as objects of accesses from a data processor unit to the plurality of physical disk devices, said method comprising the steps of:

allocating data of 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;

calculating a sequential access ratio for each of the logical disk devices;

selecting, according to results of said calculating step, a logical disk device which has a sequential access ratio exceeding a first predetermined value and a second physical disk device enabling a sequential access having a speed higher than a speed of a first physical disk device to which the logical disk device is allocated; and

reallocating contents of the logical disk device to the second physical disk device.