Method of utilizing storage disks of differing capacity in a single storage volume in a hierarchial disk array

• US 5,696,934 A
• Filed: 02/11/1997
• Issued: 12/09/1997
• Est. Priority Date: 06/22/1994
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Jacobson, Michael B., Nelson, Marvin D.
• Primary Examiner(s): SHAH, ALPESH
• Application Number:
  US08/797,214
• Time in Patent Office: 301 Days
• Field of Search: 395/404-406, 395/438-441, 395/444, 395/497.01, 395/497.02, 395/497.03, 395/497.04, 395/500, 395/800, 395/825, 395/833, 371/10.2, 371/21.1, 371/40.1
• US Class Current: 714/5.11
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• CPC Class Codes: G06F 12/0292 using tables or multilevel address translation means G06F12/023 takes precedence; address translation in virtual memory systems G06F12/10
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G11B 20/1833 by adding special lists or symbols to the coded information G11B20/1806, G11B20/1866 take precedence
• CPC Class Codes: G11C 29/74 using duplex memories, i.e. using dual copies

Abstract

The methods concern fully utilizing storage capacity in a heterogenous hierarchic disk array having storage disks of differing capacities. The disks are segmented into multiple regions. One method links non-contiguous regions from individual storage disks to form RAID areas. The RAID areas are mapped into a virtual storage space that provides a view of the physical storage space as a single storage volume. Data is then stored in these RAID areas according to different redundancy criteria, such as RAID Level 1 and RAID Level 5. A second method fully utilizes of storage capacity by configuring the heterogeneous disk array to employ a minimum of two equal-sized storage disks that have larger capacity than other individual storage disks in the disk array. The contiguous regions across the multiple disks are then grouped together to form the RAID areas.

Claims

1. A method for utilizing storage capacity in a data storage system having a heterogeneous hierarchic disk array of multiple storage disks of different physical storage capacities, the storage disks defining a total physical storage space;

the method comprising the following steps;

(a) configuring the disk array to include at least two larger storage disks with equal physical storage capacity where the physical storage capacity of the at least two storage disks is greater than the physical storage capacities of other storage disks in the disk array;

(b) segmenting the storage disks in the disk array into multiple regions;

(c) forming RAID areas from contiguous regions on multiple storage disks, the contiguous regions for each RAID area representing physical storage space at a same physical address on individual storage disks;

(d) mapping the RAID areas into a virtual storage space that provides a view of the physical storage space as a single storage volume; and

(e) storing data in the RAID areas according to selected RAID levels where each RAID area stores some redundant data.

2. A method according to claim 1 wherein the data stored in a RAID area is stored according to a RAID level selected from a group consisting of RAID Level 1 and RAID Level 5.

3. A method according to claim 1 wherein data is migrated to RAID Level 5 as storage capacity of the disk array approaches full usage so that a proportion of data stored in the disk array according to RAID Level 5 in relation to data stored in the disk array according to RAID Level 1 increases to thereby optimize efficient use of the physical storage space.

4. A method for utilizing storage capacity in a data storage system having a heterogeneous hierarchic disk array of multiple storage disks of different physical storage capacities, the storage disks defining a total physical storage space;

the method comprising the following steps;

(a) configuring the disk array to include multiple storage disks having different physical storage capacities;

(b) segmenting the storage disks of different physical storage capacities into multiple regions;

(c) linking non-contiguous regions from individual storage disks to form RAID areas, the non-contiguous regions representing physical storage space at different physical addresses on the multiple storage disks;

(d) mapping the RAID areas into a virtual storage space that provides a view of the physical storage space as a single storage volume; and

(e) storing data in the RAID areas according to selected RAID levels where each RAID area stores some redundant data.

5. A method according to claim 4 wherein the linking step (b) comprises connecting the non-contiguous regions using a pointer chaining technique where individual regions point to the next region in the linked RAID area.

6. A method according to claim 4 wherein the selected RAID levels for storing data in step (d) is chosen from a group consisting of RAID Level 1 and RAID Level 5.

7. A method according to claim 4 wherein data is migrated to RAID Level 5 as storage capacity of the disk array approaches full usage so that a proportion of data stored in the disk array according to RAID Level 5 in relation to data stored in the disk array according to RAID Level 1 increases to thereby optimize efficient use of the physical storage space.

8. A method for utilizing storage capacity in a data storage system having a heterogeneous hierarchic disk array of multiple storage disks of different physical storage capacities, comprising the following steps:

segmenting the storage disks of different physical storage capacities in the heterogeneous disk array into multiple regions;

forming first and second RAID areas from the regions of the storage disks;

storing data in the first RAID areas according to a first RAID level and in the second RAID areas according to a second RAID level; and

migrating data from one of the first RAID areas to one of the second RAID areas so that data once stored according to the first RAID level is now stored according to the second RAID level.