System and method for multiplexed data back-up to a storage tape and restore operations using client identification tags

• US 6,487,644 B1
• Filed: 11/22/1996
• Issued: 11/26/2002
• Est. Priority Date: 11/22/1996
• Status: Expired due to Term

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Veritas Operating Corporation (Gen Digital Inc.)
• Inventors: Prieve, Robert J., Huebsch, Richard J., Kampa, Leonard
• Primary Examiner(s): Gossage, Glenn
• Application Number:
  US08/755,004
• Time in Patent Office: 2,195 Days
• Field of Search: 711/161, 711/162, 711/207, 711/4, 395/200.33, 395/200.43, 395/200.44, 395/200.45, 395/200.46, 395/182.04, 395/182.05, 395/182.18, 370/216, 370/235, 709/203, 709/213, 709/214, 709/215, 709/216, 714/5, 714/6, 714/20, 710/52, 710/56, 710/57
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1461 Backup scheduling policy
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: H04L 67/01 Protocols

Abstract

A system and method for backing up and restoring data from client computers at a server computer. The server computer receives back-up data from individual client computers and inserts them into a configurable buffer within a shared memory area. The server associates a client identification (ID) tag with each set of back-up data which identifies from which particular client computer the data was received. Buffer availability flags determine whether a buffer associated with a client server is full or available. The server multiplexes the back-up data and the identification tags onto a tape. Data from a particular client is de-multiplexed from the tape by scanning all of the identification tags on the tape and pulling off the tape any data-which is associated with the identification tag corresponding to the particular client. An additional back-up scheduler unit using configurable parameters enables the entire multiplexed data back-up process to be tailored to the performance capabilities of an individual set of client/server computer resources such as by limiting how many client computer back-up jobs may be written to a single tape drive.

Claims

1. A method of backing up data from client computers at a server computer on a network comprising the steps of:

concurrently receiving data from the client computers at the server computer;

buffering the received data at the server computer; and

multiplexing the buffered data onto a single tape,

wherein the server computer includes a shared memory having a respective client computer memory block with a plurality of buffers associated with each client computer and having a plurality of buffer availability flags each associated with a respective one of the plurality of buffers and capable of being set to either empty or full.

2. The method of claim 1 further comprising a step of defining configuration parameters including a maximum number of client computers whose data can be multiplexed onto the single tape, a maximum number of jobs from a schedule that can be multiplexed onto any of a plurality of tapes, a maximum number of jobs that may be run concurrently for any class, and a maximum number of jobs that may be received concurrently from a client computer.

3. The method of claim 1 wherein the step of concurrently receiving data provides, for each of the client computers, a reading process that concurrently monitors the network for data from the respective client computer.

4. The method of claim 3 wherein each buffer comprises a data structure for storing a respective client identification tag identifying each of the client computers and associated client computer data.

5. The method of claim 4 wherein each reading process creates the client identification tag and directs a subsequent process to place associated client computer data into the buffer having its buffer availability flag set to empty.

6. The method of claim 5 wherein the step of multiplexing provides a writing process in communication with the reading process and operable to scan the buffers, to copy the client identification tag and the copied client computer data from each buffer having its availability flag set to full, to write the copied client identification tag and the client computer data to the single tape, and to set the availability flag to empty for each buffer having data copied to the single tape.

7. The method of claim 6 further comprising a step of de-multiplexing the multiplexed data, the de-multiplexing step including a de-multiplexing process operable to receive a selected client identification tag from a requesting client computer, read the single tape, locate the selected client identification tag, discard the client identification tag, and transmit the associated client computer data to the requesting client computer.

8. The method of claim 6 further comprising a step of de-multiplexing the multiplexed data, the de-multiplexing step including a de-multiplexing process operable to receive a selected client identification tag from a requesting client computer, read the tape, locate the selected client identification tag, discard the client identification tag, and write the associated client computer data to a destination tape.

9. A system for backing up data from client computers at a server computer on a network, comprising:

means for concurrently receiving data from the client computers at the server computer;

means for buffering the received data at the server computer; and

means for multiplexing the buffered data onto a single tape,

wherein the server computer includes a shared memory having a respective client computer memory block with a plurality of buffers associated with each client computer and having a plurality of buffer availability flags each associated with a respective one of the plurality of buffers and capable of being set to either empty or full.

10. The system of claim 9 further comprising means for defining configuration parameters including a maximum number of client computers whose data can be multiplexed onto the single tape, a maximum number of jobs from a schedule that can be multiplexed onto any of a plurality of tapes, a maximum number of jobs that may be run concurrently for any class, and a maximum number of jobs that may be received concurrently from a client computer.

11. The system of claim 9 wherein the means for concurrently receiving data provides, for each of the client computers, a reading process that concurrently monitors the network for data from the respective client computer.

12. The system of claim 11 wherein each buffer comprises a data structure for storing a respective client identification tag identifying each of the client computers and associated client computer data.

13. The system of claim 12 wherein each reading process creates the client identification tag and directs a subsequent process to place associated client computer data into the buffer having its buffer availability flag set to empty.

14. The system of claim 13 wherein the means for multiplexing comprises a writing process in communication with the reading process and operable to scan the buffers, copy the client identification tag and the client computer data from each buffer having its availability flag set to full, write the copied client identification tag and the client computer data to the single tape, and set the availability flag to empty for each buffer having data copied to the single tape.

15. The system of claim 14 further comprising a means for de-multiplexing, the means for de-multiplexing including a de-multiplexing process, the de-multiplexing process operable to receive a selected client identification tag from a requesting client computer, read the single tape, locate the selected client identification tag, discard the client identification tag, and transmit the associated client computer data to the requesting client computer.

16. The system of claim 14 further comprising a means for de-multiplexing, the means for de-multiplexing including a de-multiplexing process, the de-multiplexing process operable to receive a selected client identification tag from a requesting client computer, read the single tape, locate the selected client identification tag, discard the client identification tag, and transmit the associated client computer data to a destination tape.

17. A computer-readable medium embodying program code for causing a computer to back up data from client computers at a server computer on a network, comprising:

a code segment for concurrently receiving data from the client computers at the server computer;

a code segment for buffering the received data at the server computer; and

a code segment for multiplexing the buffered data onto a single tape,

wherein the server computer includes a shared memory having a respective client computer memory block with a plurality of buffers associated with each client computer and having a plurality of buffer availability flags each associated with a respective one of the plurality of buffers and capable of being set to either empty or full.

18. The computer-readable medium of claim 17 further comprising a code segment for defining configuration parameters including a maximum number of client computers whose data can be multiplexed onto the single tape, a maximum number of jobs from a schedule that can be multiplexed onto any of a plurality of tapes, a maximum number of jobs that may be run concurrently for any class, and a maximum number of jobs that may be received concurrently from a client computer.

19. The computer-readable medium of claim 17 wherein the code segment for concurrently receiving data provides, for each of the client computers, a reading process that concurrently monitors the network for data from the respective client computer.

20. The computer-readable medium of claim 19 wherein each buffer comprises a data structure for storing a respective client identification tag identifying each of the client computers and associated client computer data.

21. The computer-readable medium of claim 20 wherein each reading process creates the client identification tag and directs a subsequent process to place associated client computer data into the buffer having its buffer availability flag set to empty.

22. The computer readable medium of claim 21 wherein the code segment for multiplexing provides a writing process in communication with the reading process and operable to scan the buffers, to copy the client identification tag and the client computer data from each buffer having its availability flag set to fill, to write the copied client identification tag and the copied client computer data to the single tape, and to set the availability flag to empty for each buffer having data copied to the single tape.

23. The computer-readable medium of claim 21 further comprising a code segment for de-multiplexing the multiplexed data, the code segment for de-multiplexing the multiplexed data including a code segment for receiving a selected client identification tag from a requesting client computer, reading the single tape, locating the selected client identification tag, discarding the client identification tag, and transmitting the associated client computer data to the requesting client computer.

24. The computer-readable medium of claim 23 further comprising a code segment for de-multiplexing the multiplexed data, the code segment for de-multiplexing the multiplexed data including a code segment for receiving a selected client identification tag from a requesting client computer, reading the single tape, locating the selected client identification tag, discarding the client identification tag, and transmitting the associated client computer data to a destination tape.