Checking for proper locations of storage devices in a storage device array

• US 5,751,936 A
• Filed: 05/13/1996
• Issued: 05/12/1998
• Est. Priority Date: 11/15/1991
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Larson, David, Edstrom, Gene, Stubbs, Robert E.
• Primary Examiner(s): Chan, Eddie P.
• Assistant Examiner(s): BRAGDON, REGINALD GLENWOOD
• Application Number:
  US08/645,124
• Time in Patent Office: 729 Days
• Field of Search: 395/441, 395/182.05, 395/183.18, 395/183.12, 395/183.13
• US Class Current: 714/6.32
• CPC Class Codes: G06F 11/006 Identification G06F11/2289 takes precedence
• CPC Class Codes: G06F 11/1415 at system level
• CPC Class Codes: G06F 11/2289 by configuration test
• 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: 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 3/0634 by changing the state or mode of one or more devices
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: G11B 19/00 Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
• CPC Class Codes: G11B 19/12 by sensing distinguishing features of or on records, e.g. diameter end mark
• CPC Class Codes: G11B 20/1816 Testing
• CPC Class Codes: G11C 29/88 with partially good memories

Abstract

A determination is made as to whether or not storage devices of a storage array are positioned in their proper physical locations in the array. To make the determination, a device identifier for each of the storage devices is utilized, together with a generated logical identifier. In a preferred embodiment, the device identifier is the serial number for the storage device and the logical identifier includes a combination of all the device identifiers for a particular logical volume of the storage array. Preferably, the logical identifier also includes system status information for use in enhancing fault tolerance. The logical identifier is written or updated upon the occurrence of predetermined events or conditions. Using the device identifiers and the logical identifier, an indication can be provided whenever the proper storage devices are not found in the logical volume whereby corrective action can be taken to avoid improper distribution to or reassembly of data from the logical volume.

Claims

1. A method for determining whether each of a plurality of storage devices of a logical volume of storage devices is part of a logical volume, comprising:

providing an identifier on each storage device of said logical volume, each of the identifiers on each of said storage devices being the same in said logical volume;

reading out the identifiers from each of said storage devices;

assuming the identifier read out from one of said storage devices is a reference identifier;

comparing the reference identifier with the identifier read out from the other storage devices;

determining whether or not an incorrect member is present in said logical volume based upon the comparison result in said comparing step; and

updating the identifier on each of said storage devices when an event occurs which may affect data integrity, by generating a new identifier different from that already provided on said storage devices, and writing the new identifier to each of said storage devices.

2. A method, as claimed in claim 1, wherein:

said event includes at least one of the following;

initialization of said storage devices by updating defect maps and allocation of data storage,

reconstruction of data for one of said storage devices, and

a configuration change by storing data on a replacement storage device for one of said storage devices that is failed.

3. A method, as claimed in claim 1, wherein:

the identifier includes status information comprising status related to said event.

4. A method for determining whether each of a plurality of storage devices of a logical volume of storage devices is part of a logical volume, comprising:

providing an identifier on each storage device of said logical volume, each of the identifiers on each of said storage devices being the same in said logical volume;

reading out the identifiers from each of said storage devices;

assuming the identifier read out from one of said storage devices is a reference identifier;

comparing the reference identifier with the identifier read out from the other storage devices;

determining whether or not an incorrect member is present in said logical volume based on the comparison result in said comparing step; and

updating the identifier on each of said storage devices, when an event occurs which may affect data integrity, by generating a new identifier different from that already provided on said storage devices and writing the new identifier to each of said storage devices, said event relates to disruption of power to at least one of said storage devices after reconstruction of data has begun associated with said storage devices.

5. A disk array apparatus connected to a plurality of storage devices of a logical volume, comprising:

means for providing an identifier on each of said storage devices of said logical volume, each of the identifiers being the same in said logical volume;

means for reading out the identifiers from each of said storage devices of said logical volume;

means for assuming the identifier read out from one of said storage devices as a reference identifier;

means for comparing the reference identifier with the identifier read out from each of the other storage devices of said logical volume;

means for determining whether or not an incorrect member is present in said logical volume based upon the comparison result of said comparing means; and

means for updating the identifier on each of said storage devices when an event occurs which may affect data integrity, by generating a new identifier different from that already provided on said storage devices, and writing the new identifier to each of said storage devices.

6. An apparatus, as claimed in claim 5, wherein:

said event includes at least one of the following;

initialization of said storage devices by updating defect maps and allocation of data storage,

reconstruction of data from one of said storage devices, and

a configuration change by storing data on a replacement storage device for one of said storage devices that is failed.

7. An apparatus, as claimed in claim 5, wherein:

the identifier includes status information comprising status related to said event.

8. A disk array apparatus connected to a plurality of storage devices of a logical volume, comprising:

means for providing an identifier on each of said storage devices, of said logical volume, each of the identifiers being the same in said logical volume;

means for reading out the identifiers from each of said storage devices of said logical volume;

means for assuming the identifier read out from one of said storage devices as a reference identifier;

means for comparing the reference identifier with the identifier read out from each of the other storage devices of said logical volume;

means for determining whether or not an incorrect member is present in said logical volume based upon the comparison result of said comparing means; and

means for updating the identifier on each of said storage devices when an event occurs which may affect data integrity by generating a new identifier different from that already provided on said storage devices and writing the new identifier to each of said storage devices, said event relates to a disruption of power to one of said storage devices after reconstruction of data on said storage devices has begun.

9. A method for determining whether each of a plurality of storage devices of a logical volume of storage devices is positioned at a proper physical location, comprising:

monitoring, using processing means, occurrences of predetermined events including;

(a) initialization of said storage devices by updating defect maps and allocation of data storage.

(b) reconstruction of data for one of said storage devices, and

(c) a configuration change by storing data on a replacement storage device for one of said storage devices that has failed;

obtaining information using said processing means related to said reconstruction of data;

writing identifier means using said controller means to each storage device of said logical volume of said storage devices, said identifier means including status information comprising status related to each of said predetermined events including first status related to said reconstruction of data after said obtaining step;

beginning execution of said reconstruction of data using at least one of said processing means and said controller means;

powering on at least one of said storage devices after disruption of power thereto;

reading said identifier means using said controller means for each of said storage devices after said powering on step;

determining using said processing means that each of said storage devices of said logical volume is properly located in said logical volume using said identifier means;

completing execution of said reconstruction of data using at least one of said processing means and said controller means after said determining step; and

rewriting said identifier means using said controller means to each said storage device of said logical volume, said identifier means including a second status related to said reconstruction of data after said completing step.

10. A method, as claimed in claim 9 wherein:

said step of writing said identifier means includes writing said identifier means to one of said storage devices of said logical volume that is the same as said identifier means that is written to each of the other of said storage devices of said logical volume.

11. A method, as claimed in claim 9, wherein:

said rewriting said identifier means includes rewriting said identifier means to one of said storage devices of said logical volume that is the same as said identifier means that is rewritten to each of the other of said storage devices of said logical volume.

12. A method for determining whether each of a plurality of storage devices of a logical volume of storage devices is a proper member of the logical volume of storage devices, comprising:

providing an identifier on each storage device of a logical volume of storage devices, each said identifier including a device identifier that is unique to each of said storage devices of said logical volume and each said identifier including a logical identifier that includes a combination of each of said device identifiers of said storage device with said logical identifier being stored on each of said storage devices;

reading out each said identifier from each of said storage devices;

assuming said identifier read out from one of said storage devices as a reference identifier;

comparing said reference identifier with said identifier read out from the other storage devices of said logical volume; and

determining whether or not an improper member of said storage devices is in said storage devices of said logical volume based upon results of said comparing step.

13. A method, as claimed in claim 12, wherein:

said step of providing includes generating said logical identifier whenever at least one of the following occurs;

attaching of one of said storage devices, replacing one of said storage devices, updating defect information for one of said storage devices, reconstructing data for one of said storage devices, and changing configuration information associated with said logical volume.

14. A method, as claimed in claim 12, wherein:

said step of reading includes reading a serial number written on each of said storage devices, each of said serial numbers being used as a device identifier which is part of said identifier.

15. A method, as claimed in claim 12, wherein:

said step of comparing includes comparing said device identifier for each of said storage devices with a predetermined portion of said reference identifier.

16. A disk array apparatus connected to a plurality of storage devices of a logical volume, comprising:

means for providing an identifier on each of said storage devices of said logical volume, each said identifier including a device identifier that is unique to each of said storage devices of said logical volume and each said identifier including a logical identifier that includes a combination of each of said device identifiers of said storage devices with said logical identifier being stored on each of said storage devices;

means for reading out each said identifier from each of said storage devices of said logical volume;

means for assuming said identifier read out from one of said storage devices as a reference identifier;

means for comparing said reference identifier with each said identifier read out from each of said storage devices; and

means for determining whether or not an improper member of said storage devices of said logical volume is in said storage devices of said logical volume based upon results of said means for comparing.

17. An apparatus, as claimed in claim 16, wherein:

said identifier includes control bytes that have information relating to the operation of the apparatus.

18. An apparatus, as claimed in claim 16, wherein:

each said identifier includes a serial number associated with each of said storage devices.

19. An apparatus, as claimed in claim 16, wherein:

said means for determining determines whether each of said storage devices of said logical volume has the same logical identifier.

20. An apparatus, as claimed in claim 16, wherein:

said means for comparing compares each of said device identifiers with a predetermined portion of said reference identifier.