Technique for managing addition of disks to a volume of a storage system

• US 7,694,173 B1
• Filed: 08/22/2008
• Issued: 04/06/2010
• Est. Priority Date: 03/21/2003
• Status: Expired due to Fees

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Sankar, Sunitha S., Schoenthal, Scott, Cassell, Loellyn J.
• Primary Examiner(s): GUYTON, PHILIP A
• Application Number:
  US12/196,847
• Time in Patent Office: 592 Days
• Field of Search: 714/6, 714/7, 711/161, 711/162
• US Class Current: 714/6.12
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: G06F 11/0766 Error or fault reporting or storing
• CPC Class Codes: G06F 11/1096 Parity calculation or recalculation after configuration or reconfiguration of the system
• CPC Class Codes: G06F 11/1662 the resynchronized component or unit being a persistent storage device re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 12/0804 with main memory updating G06F12/0806 takes precedence
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 2211/1061 Parity-single bit-RAID4, i.e. RAID 4 implementations
• 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 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A technique manages the addition of disks to a volume of a storage system. A disk addition procedure is encapsulated into a DISKADD object conforming to a configuration management framework used to implement a RAID subsystem of the storage system. The DISKADD object is responsible for determining a set of available disks required to satisfy a disk addition request issued by an operator through a user interface of a storage operating system executing on the storage system. Furthermore, the DISKADD object is responsible for monitoring the state of the disks, including preparation/initialization of the disks (e.g., disk zeroing) and possible disk failures, as well as placing those disks into RAID groups of the volume once preparation completes. Persistent storage of the state of a pending disk addition is then accomplished using an implementation of the configuration management framework.

Claims

1. A method for managing addition of disks to a volume of a storage system, comprising:

implementing a redundant array of independent disks (RAID) subsystem in a storage operating system of the storage system using a configuration management framework;

issuing a disk addition request to the RAID subsystem; and

encapsulating a disk addition procedure into a disk addition (diskadd) object conforming to the configuration management framework, the disk addition procedure (i) determining a set of available disks required to satisfy the disk addition request, (ii) selecting one or more disks to add based on mirroring requirement, checksum characteristic, or zeroing characteristic, (iii) monitoring a state of the available disks including disk initialization and disk failures, and (iv) adding selected disks of the available disks into RAID groups once disk initialization has completed.

2. The method of claim 1, further comprising:

storing a state of the disk addition procedure on a predetermined disk to provide persistent storage of the disk addition state.

3. The method of claim 1, further comprising:

associating at least one disk container object with the diskadd object, each disk container object grouping the set of available disks and propagating disk zeroing success or failure status of each available disk to the diskadd object.

4. The method of claim 1, wherein the step of encapsulating the disk addition procedure further comprises:

encapsulating a placement procedure in the diskadd object, the placement procedure adding the selected disks into the volume.

5. The method of claim 4, wherein the step of encapsulating the placement procedure further comprises:

analyzing the selected disks against known locality and placement criteria.

6. The method of claim 1, wherein the one or more disks are selected based on characteristics from an existing RAID topology of the volume, and the existing RAID topology further comprises parity, disk sizing and RAID group size.

7. The method of claim 1, wherein an operator uses a user interface of the storage operating system to issue the disk addition request.

8. A system configured to manage addition of disks to a volume of a storage system, the system comprising:

a redundant array of independent disks (RAID) subsystem in a storage operating system of the storage system;

a user interface of the storage operating system configured to enable an operator to access the RAID subsystem by issuing a disk addition request;

a configuration management framework configured to implement the RAID subsystem, the configuration management framework providing a configuration tree organizing a plurality of objects having configuration interfaces that define a set of services; and

a disk addition (diskadd) object of the configuration tree, the diskadd object encapsulating a disk addition procedure conforming to the configuration management framework, the disk addition procedure of the diskadd object (i) determining a set of available disks required to satisfy the disk addition request, (ii) selecting one or more disks to add based on mirroring requirement, checksum characteristic, or zeroing characteristic (iii) monitoring a state of the available disks, and (iv) adding selected disks of the available disks into RAID groups.

9. The system of claim 8, wherein the state of the available disks monitored by the disk addition procedure of the diskadd object includes disk zeroing and disk failures.

10. The system of claim 9, wherein the disk addition procedure adds and places the available disks into RAID groups once disk zeroing has completed.

11. The system of claim 8, further comprising at least one disk container object associated with the diskadd object, each disk container object configured to group the set of available disks and propagate disk zeroing success or failure status of each available disk to the diskadd object.

12. The system of claim 11, wherein the diskadd object further encapsulates a placement procedure configured to add the selected disks into the volume.

13. The system of claim 12, wherein the available disks have disk characteristics including identification of a spare pool, sector size of each disk, capacity of each disk, preparation status of each disk and physical locality of the disks.

14. The system of claim 13, wherein the physical locality of the disks includes consideration of a disk shelf where the available disks are located, a disk port connection and a physical adapter in the storage system.

15. The system of claim 13, wherein the sector size disk characteristic denotes how each available disk is zoned, the sector size disk characteristic having associated parameters including a checksum type.

16. The system of claim 13, wherein the capacity disk characteristic has two components including a total size or storage space of each available disk and an actual amount of space of the available disk that is utilized.

17. The system of claim 13, wherein the preparation status includes whether the available disks have been zeroed.

18. The system of claim 11, wherein the RAID subsystem comprises a configuration thread configured to maintain relationships of the objects within the configuration tree, the configuration thread interacting on behalf of the volume to create and destroy the relationships of the objects in the configuration tree, including allocating and inserting the available disks into the volume using the diskadd and disk container objects.

19. A method for managing addition of disks to a volume of a storage system, comprising:

implementing a redundant array of independent disks (RAID) subsystem in a storage operating system of the storage system using a configuration management framework that provides a configuration tree configured to organize a plurality of objects;

issuing a disk addition request through a user interface of the storage operating system to the RAID subsystem, the disk addition request selecting a count of available disks to be added to the volume;

selecting one or more disks to add based on mirroring requirement, checksum characteristic or zeroing characteristic;

adding and allocating the selected disks to a disk container object associated with a disk addition (diskadd) object of the configuration tree, the diskadd object encapsulating a placement procedure;

rendering an initial disk placement decision using the placement procedure;

inserting the allocated disks into a RAID group of the volume;

associating the inserted disks as disk objects with respect to a RAID group object of the configuration tree to render the inserted disks capable of storing data; and

destroying the diskadd and disk container objects in accordance with a destroy method of each object.

20. The method of claim 19, further comprising:

zeroing the allocated disks in accordance with a zeroing process;

determining whether an allocated disk fails during the zeroing process;

if an allocated disk fails, issuing a failure notification from the disk container object to the diskadd object.

21. A method for managing addition of storage devices to a storage system, comprising:

determining a set of available storage devices required to satisfy a storage device addition request;

monitoring a state of the available storage devices including storage device initialization and storage device failures;

selecting one or more storage devices to add based on mirroring requirement, checksum characteristic, or zeroing characteristic; and

adding selected one or more storage devices of the available storage devices into one or more volumes once storage device initialization has completed.

22. The method of claim 21, further comprising:

storing a state of the storage device addition procedure on a predetermined storage device to provide persistent storage of the storage device addition state.

23. The method of claim 21, further comprising:

analyzing the selected disks against known locality and placement criteria.

24. The method of claim 21, wherein the one or more storage devices are selected based on characteristics from an existing topology of a volume, and the existing topology further comprises parity, disk sizing and RAID group size.