DATA STORAGE SYSTEM AND PROCESS

• US 20080162594A1
• Filed: 03/11/2008
• Published: 07/03/2008
• Est. Priority Date: 06/06/2000
• Status: Abandoned Application

• Current Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Original Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Inventors: POSTON, Lloyd Alan
• Application Number:
  US12/046,376
• Publication Number:
  US 20080162594A1
• Time in Patent Office: Days
• US Class Current: 707/202
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

Computer systems may loose data when a failure occurs within a system. To counteract such loss of data a backup system may be employed. Common backup systems make a copy of either of the data on a storage device or the data, which has changed, on a storage device. The process of backing up data may involve storing a relatively large amount of data and so is commonly done infrequently, such as once per day. If a computer'"'"'s data is backed up only once per day, several hours of data may be lost if a computer system falls. Embodiments of the present invention may be used to prevent this type of data loss by backing up more frequently. In order to back up more frequently less data at a time is backed up. Instead of the data undergoing a wholesale backup infrequently, embodiments of the present invention form a timed log of the storage writes performed by the computer system. The log provides a running picture of activity to the computer storage system. By preserving the log, for example storing it at a remote site through a network connection, the state of the computer can be recreated with any desired granularity, by using the log entries to recreate the state of the data within the computer system at any desired time.

Claims

1. A method of continuous data storage, the method comprising:

receiving a write command;

combining the received write command with time information, wherein the time information indicates when the write command was received; and

storing the write command combined with the time information.

2. The method of claim 1, wherein combining the received write command with time information comprises:

converting the received write command to a sector write having a sector address and sector data; and

combining the sector write with a time stamp to create a log entry.

3. The method of claim 2, wherein storing the write command combined with the time information comprises:

storing the log entry in a log file.

4. The method of claim 3, further comprising:

queuing the log entry before storing the log entry in the log file.

5. The method of claim 3, wherein storing the log entry in a log file comprises:

determining a sector address to be written to from a received log entry;

searching for log entries in the log file having an earlier time stamp which were written to the same sector address; and

deleting any log entries in the log file with an earlier time stamp which were written to the same sector address as the received log entry.

6. A computer-readable storage medium having computer-executable instructions for continuous data storage, comprising instructions for:

receiving a write command;

combining the received write command with time information, wherein the time information indicates when the write command was received; and

storing the write command combined with the time information.

7. The computer-readable storage medium of claim 6, wherein combining the received write command with time information comprises instructions for:

converting the received write command to a sector write having a sector address and sector data; and

combining the sector write with a time stamp to create a log entry.

8. The computer-readable storage medium of claim 7, wherein storing the write command combined with the time information comprises instructions for:

storing the log entry in a log file.

9. The computer-readable storage medium of claim 8, further comprising instructions for:

queuing the log entry before storing the log entry in the log file.

10. The computer-readable storage medium of claim 8, wherein storing the log entry in a log file comprises instructions for:

determining a sector address to be written to from a received log entry;

searching for log entries in the log file having an earlier time stamp which were written to the same sector address; and

deleting any log entries in the log file with an earlier time stamp which were written to the same sector address as the received log entry.

11. A method of continuous data storage, the method comprising:

receiving a write command;

converting the received write command to a sector write having a sector address and sector data; and

combining the sector write with a time stamp to create a log entry, wherein the time stamp indicates when the write command was received; and

storing the log entry in a log file.

12. The method of claim 11, further comprising:

queuing the log entry before storing the log entry in the log file.

13. The method of claim 11, wherein storing the log entry in a log file comprises:

determining a sector address to be written to from a received log entry;

searching for log entries in the log file having an earlier time stamp which were written to the same sector address; and

deleting any log entries in the log file with an earlier time stamp which were written to the same sector address as the received log entry.