CA2201859A1 - Snapshot of data stored on a mass storage system - Google Patents

Snapshot of data stored on a mass storage system

Info

Publication number
CA2201859A1
CA2201859A1 CA2201859A CA2201859A CA2201859A1 CA 2201859 A1 CA2201859 A1 CA 2201859A1 CA 2201859 A CA2201859 A CA 2201859A CA 2201859 A CA2201859 A CA 2201859A CA 2201859 A1 CA2201859 A1 CA 2201859A1
Authority
CA
Canada
Prior art keywords
block
mass storage
storage system
virtual device
data stored
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CA2201859A
Other languages
French (fr)
Other versions
CA2201859C (en
Inventor
Richard S. Ohran
Michael R. Ohran
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EMC Corp
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US08/322,697 external-priority patent/US5649152A/en
Application filed by Individual filed Critical Individual
Publication of CA2201859A1 publication Critical patent/CA2201859A1/en
Application granted granted Critical
Publication of CA2201859C publication Critical patent/CA2201859C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Landscapes

  • Debugging And Monitoring (AREA)
  • Information Retrieval, Db Structures And Fs Structures Therefor (AREA)

Abstract

A method for providing a static snapshot, or image, of data stored on a mass storage system (104). At the start of the method, a preservation memory (106) is cleared and a virtual device is created. Whenever a write is to be performed on the mass storage system (104), a check is made of the preservation memory (106) to determine if it contains a block associated with the mass storage write address.
If there is not, a copy of the block in the mass storage system (104) at the block write address is placed in the preservation memory (106).
Whenever a read is to be performed on the virtual device, a check is made of the preservation memory (106) to determine if it contains a block associated with the virtual device read address. If there is such a block, that block is returned as the result of the virtual device read.
Otherwise, the block at the virtual device block read address is returned as the result.
CA002201859A 1994-10-13 1995-10-10 Snapshot of data stored on a mass storage system Expired - Fee Related CA2201859C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US08/322,697 US5649152A (en) 1994-10-13 1994-10-13 Method and system for providing a static snapshot of data stored on a mass storage system
US08/322,697 1994-10-13
PCT/US1995/013324 WO1996012232A1 (en) 1994-10-13 1995-10-10 Snapshot of data stored on a mass storage system

Publications (2)

Publication Number Publication Date
CA2201859A1 true CA2201859A1 (en) 1996-04-25
CA2201859C CA2201859C (en) 2000-12-19

Family

ID=29422765

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002201859A Expired - Fee Related CA2201859C (en) 1994-10-13 1995-10-10 Snapshot of data stored on a mass storage system

Country Status (1)

Country Link
CA (1) CA2201859C (en)

Also Published As

Publication number Publication date
CA2201859C (en) 2000-12-19

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