Method for managing logical volume in order to support dynamic online resizing and software raid and to minimize metadata and computer readable medium storing the same

• US 6,718,436 B2
• Filed: 12/07/2001
• Issued: 04/06/2004
• Est. Priority Date: 07/27/2001
• Status: Expired due to Term

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Kim, Chang-Soo, Kim, Gyoung Bae, Shin, Bum Joo
• Primary Examiner(s): Gossage, Glenn
• Application Number:
  US10/005,604
• Publication Number:
  US 20030023811A1
• Time in Patent Office: 851 Days
• Field of Search: 711/114, 711/170, 711/112
• US Class Current: 711/114
• 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

Abstract

A method for managing a logical volume for minimizing a size of metadata and supporting dynamic online resizing and software redundant array of independent disks (RAID), and a computer-readable recording medium storing instructions for embodying the method, are disclosed. The method includes the metadata having a disk partition table containing information of a disk partition in which the metadata is stored; a logical volume table for maintaining the information of the logical volume by storing duplicated information of the logical volume onto all disk partitions of the logical volume; an extent allocation table for indicating whether each extent in the disk partitions is used or not; and a mapping table for maintaining a mapping information for a physical address space corresponding to a logical address space which is a continuous address space equal in size of storage space of whole logical volume.

Claims

1. A method for managing a logical volume in order to support dynamic online resizing and minimizing a size of metadata, said method comprising steps of:

a) creating the logical volume by gathering disk partitions in response to a request for creating the logical volume in a physical storage space;

b) generating the metadata including information of the logical volume and the disk partitions forming the logical volume and storing the metadata to the disk partitions forming the logical volume;

c) dynamically resizing the logical volume in response to a request for resizing, and modifying the metadata on the disk partitions forming the logical volume; and

d) calculating and returning a physical address corresponding to a logical address of the logical volume by using mapping information of the metadata containing information of the physical address corresponding to the logical address;

wherein the metadata includes,

a disk partition table containing information of a disk partition in which the metadata is stored;

a logical volume table for maintaining the information of the logical volume by storing duplicated information of the logical volume onto all disk partitions of the logical volume;

an extent allocation table for indicating whether each extent in the disk partition is used or not used; and

a mapping table for maintaining a mapping information for a physical address space corresponding to a logical address space which is a continuous address space equal in size of storage space to an entirety of said logical volume.

2. The method as recited in claim 1, wherein the mapping table is divided into parts corresponding in number to a number of disk partitions forming the logical volume and each divided part is stored to each disk partition.

3. The method as recited in claim 1, wherein the metadata further includes a mirror data table for validating data located on several disk partitions corresponding to each mirror by maintaining the mirror data table in disk partitions constructing each mirror and storing the mirror data table to each corresponding mirror in an overlapped manner.

4. The method as recited in claim 1, wherein

said disk partition table includes the logical volume information to which the disk partitions containing the metadata belong, information for identifying the disk partitions, real data start information, an extent size information of the disk partitions defined in the logical volume, and mirror checking information;

said logical volume table is duplicated and stored in all disk partitions forming the logical volume including logical volume identifying information corresponding to the logical volume, logical volume name information, extent size information of the logical volume, redundant array of independent disk (RAID) level information of construction type of the logical volume, and a total number of disk partitions forming the logical volume;

said extent allocation table represents usage of each extent by using one bit per each extent in disk partition; and

said mapping table being constructed with a pair of the disk partitions identifying information and an extent number corresponding to each extent for mapping a logical address to a physical address.

5. The method as recited in claim 4, wherein the extent allocation table is duplicated and stored in the disk partition for overcoming a local error of a disk partition which contains the metadata.

6. The method as recited in claim 4, wherein the mapping table is duplicated and stored into the succeeding disk partition among disk partitions constructing a logical volume for preventing unavailability of mapping information caused by an error.

7. The method as recited in claim 4, wherein the metadata further includes a mirror data table located on disk partitions storing original data or mirror data, and the mirror data table is constructed with bits corresponding in number to the number of disk partitions having at least one mirror data or the original data per one extent for validating a corresponding extent of each corresponding disk partition.

8. A computer-readable recording medium storing instructions for executing a method for managing a logical volume in order to support dynamic online resizing and minimizing a size of metadata, said method comprising the steps of:

a) creating the logical volume by gathering disk partitions in response to a request for creating the logical volume in a physical storage space;

b) generating the metadata including information of the logical volume and the disk partitions forming the logical volume and storing it the metadata to the disk partitions forming the logical volume;

c) dynamically resizing the logical volume in response to a request for resizing, and modifying the metadata on the disk partitions forming the logical volume; and

d) calculating and returning a physical address corresponding to a logical address of the logical volume by using mapping information of the metadata containing information of the physical address corresponding to the logical address;

wherein the metadata includes,

a disk partition table containing information of a disk partition in which the metadata is stored;

a logical volume table for maintaining the information of the logical volume by storing duplicated information of the logical volume onto all disk partitions of the logical volume;

an extent allocation table for indicating whether each extent in the disk partition is used or not used; and

a mapping table for maintaining a mapping information for a physical address space corresponding to a logical address space which is a continuous address space equal in size of storage space to an entirety of said logical volume.

9. The computer-readable recording medium storing instructions for executing a logical volume management method, as recited in claim 8, wherein

said disk partition table includes logical volume information, information for identifying the disk partitions, real data starting information, extent size information of the disk partitions defined in the logical volume, and mirror checking information;

said logical volume table is duplicated and stored in all disk partitions forming logical volume including logical volume identifying information corresponding to the logical volume, logical volume name information, extent size information of the logical volume, redundant array of independent disk (RAID) level information of construction type of the logical volume, and a total number of disk partitions forming the logical volume;

said extent allocation table is duplicated and stored in the disk partition for resolving a local error of disk partition, which is for representing usage of each extent by using one bit per each extent in disk partition; and

said mapping table is constructed with a pair of the disk partitions identifying information and an extent number corresponding to each extent for mapping a logical address to a physical address.

10. The computer-readable recording medium as recited in claim 9, wherein the mapping table is divided into parts corresponding in number to the number of disk partitions forming the logical volume and each divided part is stored to each disk partition.

11. A method for managing a logical volume in order to support dynamic online resizing and minimizing a size of metadata, said method comprising steps of:

a) creating the logical volume by gathering disk partitions in response to a request for creating the logical volume in a physical storage space;

b) generating the metadata including information of the logical volume and the disk partitions forming the logical volume and storing the metadata to the disk partitions forming the logical volume;

c) dynamically resizing the logical volume in response to a request for resizing, and modifying the metadata on the disk partitions forming the logical volume; and

d) calculating and returning a physical address corresponding to a logical address of the logical volume by using mapping information of the metadata containing information of the physical address corresponding to the logical address;

wherein the metadata includes;

a disk partition table including the logical volume information to which the disk partition containing the metadata belongs, information for identifying the disk partition, real data start information, an extent size information of the disk partition defined in the logical volume, and mirror checking information;

a logical volume table duplicated and stored in all disk partitions constructing corresponding logical volume including logical volume identifying information corresponding to the logical volume, logical volume name information, extent size information of the logical volume, RAID level information of construction type of the logical volume, and total number of disk partitions constructing the logical volume;

an extent allocation table for representing usage of the extent by using one bit per each extent in the disk partition; and

a mapping table being constructed with a pair of the disk partition identifying information and an extent number corresponding to each extent for mapping a logical address to a physical address, for continuous logical address space of a logical volume.

12. The method as recited in claim 11, wherein the extent allocation table is duplicated and stored in the disk partition for overcoming a local error of a disk partition which contains the metadata.

13. The method as recited in claim 11, wherein the mapping table is duplicated and stored into the succeeding disk partition among disk partitions constructing a logical volume for preventing unavailability of mapping information caused by an error.

14. The method as recited in claim 11, wherein the metadata further includes a mirror data table located on disk partitions storing original data or mirror data, and the mirror data table is constructed with bits corresponding in number to the number of disk partitions having at least one mirror data or the original data per one extent for validating a corresponding extent of each corresponding disk partition.