Apparatus and method to archive log entries formed by a data storage system

• US 7,778,974 B2
• Filed: 10/14/2007
• Issued: 08/17/2010
• Est. Priority Date: 10/14/2007
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Compton, Matthew Charles, Lehmann, Stefan
• Primary Examiner(s): Vo; Tim T.
• Assistant Examiner(s): Sanders; Aaron
• Application Number:
  US11/872,016
• Publication Number:
  US 20090100111A1
• Time in Patent Office: 1,038 Days
• Field of Search: None
• US Class Current: 707/648
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

A method to archive log entries created by a data storage system comprising a first memory and a library log encoded in that first memory, wherein the first memory comprises a storage capacity, and wherein the method writes a plurality of log entries to the library log, wherein each log entry comprises a log entry time. At a time T₀, the method copies to a log archive the plurality of log entries written to the library log, and sets a subsequent retrieval time based upon a time T₁ when an earliest log entry was written to the library log, and a time T₂ when a latest log entry was written to the library log.

Claims

1. A method to archive log entries created by a data storage system, comprising the steps of:

providing a data storage system comprising first memory and a library log encoded in said first memory;

writing a plurality of log entries to said library log, wherein each log entry comprises a log entry time;

encoding a log archive in a second memory, wherein said second memory is external to said data storage system;

setting a time T₀ equal to current time;

at time T₀, copying to said log archive said plurality of log entries written to said library log;

determining a time T₁ when an earliest log entry was written to said library log;

determining a time T₂ when a latest log entry was written to said library log;

calculating a log interval T_INT equal to (T₂−

T₁);

setting a retrieval time equal to (T₀+T_INT);

determining whether to perform an intermediate inspection of the library log;

when performing an intermediate inspection of the library log, determining a number (N) of log entries written to library log retrieved at time T₀;

establishing a previous log filling rate equal to (N)/T_INT;

setting an intermediate sampling interval T_S, wherein said intermediate sampling interval is less than said log interval;

setting an intermediate sampling time, wherein said intermediate sampling time equals (T₀+T_S);

when current time equals said intermediate sampling time, inspecting the library log created after time T₀;

determining a number (M) of log entries written to the library log after time T₀;

establishing a current log filling rate equal to (M)/T_S;

determining whether said current log filling rate is greater than said previous log filling rate; and

when said current log filling rate is greater than said previous log filling rate, adjusting said log interval T_INT to be less than (T₂−

T₁).

2. The method of claim 1, further comprising the steps of:

setting a minimum log interval;

determining if said adjusted log interval is less than said minimum log interval; and

when said adjusted log interval is less than said minimum log interval, setting said log interval equal to said minimum log interval.

3. The method of claim 1, further comprising the steps of:

when said current log filling rate is not greater than said previous log filling rate, determining if said current log filling rate is less than said previous log filling rate; and

when said current log filling rate is less than said previous log filling rate, adjusting said log interval T_INT to be greater than (T₂−

T₁).

4. An article of manufacture comprising a processor and a computer readable storage medium having computer readable program code disposed therein to archive a plurality of log entries stored by a data storage system in a first memory, wherein each log entry comprises a log entry time, the computer readable program code comprising a series of computer readable program steps to effect:

encoding a log archive in a second memory, wherein said second memory is external to said data storage system;

setting a time T₀ equal to current time;

at time T₀, copying to said log archive said plurality of log entries written to said library log;

determining a time T₁ when an earliest log entry was written to said library log;

determining a time T₂ when a latest log entry was written to said library log;

calculating a log interval T_INT equal to (T₂−

T₁);

setting a retrieval time equal to (T₀+T_INT);

determining whether to perform an intermediate inspection of the library log;

when performing an intermediate inspection of the library log, determining a number (N) of log entries written to library log retrieved at time T₀;

establishing a previous log filling rate equal to (N)/T_INT;

setting an intermediate sampling interval T_S, wherein said intermediate sampling interval is less than said log interval;

setting an intermediate sampling time, wherein said intermediate sampling time equals (T₀+T_S);

when current time equals said intermediate sampling time, inspecting the library log created after time T₀;

determining a number (M) of log entries written to the library log after time T₀;

establishing a current log filling rate equal to (M)/T_S;

determining whether said current log filling rate is greater than said previous log filling rate; and

when said current log filling rate is greater than said previous log filling rate, adjusting said log interval T_INT to be less than (T₂−

T₁).

5. The article of manufacture of claim 4, said computer readable program code further comprising a series of computer readable program steps to effect:

setting a minimum log interval;

determining whether said adjusted log interval is less than said minimum log interval; and

when said adjusted log interval is less than said minimum log interval, setting said log interval equal to said minimum log interval.

6. The article of manufacture of claim 4, said computer readable program code further comprising a series of computer readable program steps to effect:

when said current log filling rate is not greater than said previous log filling rate, determining if said current log filling rate is less than said previous log filling rate; and

when said current log filling rate is less than said previous log filling rate, adjusting said log interval TINT to be greater than (T2−

T1).