Disk recovery/reconstruction

A method of recovering a data base from a failure of at least one of a plurality of physical disk drives wherein the plurality of physical disk drives are coupled to a transaction based data processing system utilizing a plurality of transactions, the at least one of the plurality of physical disk drives storing contents, said method comprising the steps of:

• a. generating a plurality of transaction records and compiling each of said plurality of transaction records into an audit trail record upon processing each of said plurality of transactions, said audit trail record having a plurality of portions wherein each of the plurality of portions corresponds to one of the plurality of transactions, each of said plurality of transaction records comprising at least one changed word having a content and a location therein;
• b. storing said plurality of portions of said audit trail record in a plurality of separate audit trail storage areas, each of said plurality of separate audit trail storage areas being coupled to a corresponding one of said plurality of physical disk drives, each of said plurality of transactions being associated with one of said plurality of physical disk drives and thus being associated with a corresponding one of said plurality of separate audit trail storage areas, said storing step (b) storing each of said plurality of portions of said audit trail record in a corresponding one of said plurality of separate audit trail storage areas;
• c. dumping each of the plurality of physical disk drives to a different one of a plurality of redundant storage facilities before the failure of said at least one of the plurality of physical disk drives, said plurality of redundant storage facilities being coupled to said plurality of physical disk drives;
• and
• d. reconstructing the contents of the at least one of said plurality of physical disk drives after the failure of the at least one of the plurality of physical disk drives using a corresponding one of said plurality of redundant storage facilities and using said corresponding one of said plurality of separate audit trail storage areas.

An apparatus comprising:

• a. a plurality of storage devices for storing a data base;
• b. transaction processing system coupled to said plurality of storage devices for modifying said data base in response to a series of transactions;
• c. an audit trail storage area coupled to said transaction processing system for storing a record of said modifying of said data base in response to said series of transactions;
• and
• d. a data base dump facility coupled to said transaction processing system for storing said data base in response to a filling of said audit trail storage area.

In a digital data processing system having a plurality of separate storage elements wherein said plurality of separate storage elements store a data base, said digital data processing system posting transactions to the data base, the improvement comprising:

• a. a processor which is programmed for generating a plurality of transaction records and compiling each of said plurality of transaction records into audit trail data corresponding to each of the transactions, each of said plurality of transaction records comprising at least one changed word having a content and a location therein;
• b. a segregating circuit coupled to said processor for segregating the audit trail data prepared for each of the transactions according to a corresponding one of the plurality of separate storage elements such that said segregated audit trail data corresponds to said corresponding one of the plurality of separate storage elements;
• and
• c. a plurality of memory elements coupled to said segregating circuitry for separately storing the segregated audit trail data such that said separately stored segregated audit trail data corresponds to said corresponding one of the plurality of separate storage elements.

In a digital data processing system having a plurality of separate storage elements wherein said plurality of separate storage elements store a data base, said digital data processing system posting transactions to the data base, the improvement comprising:

• a. a processor which is programmed for generating a plurality of transaction records and compiling each of said plurality of transaction records into audit trail data corresponding to each of the transactions, each of said plurality of transaction records comprising at least one changed word having a content and a location therein;
• b. a segregating circuit coupled to said processor for segregating the audit trail data prepared for each of the transactions according to a corresponding one of a plurality of files within the data base;
• and
• c. a plurality of memory elements coupled to said segregating circuitry for separately storing the segregated audit trail data.

A method of recovering a data base from a failure of at least one of a plurality of logical files wherein the plurality of logical files are coupled to a transaction based data processing system utilizing a plurality of transactions, the at least one of the plurality of logical files storing contents, said method comprising the steps of:

• a. generating a plurality of transaction records and compiling each of said plurality of transaction records into an audit trail record upon processing each of said plurality of transactions, said audit trail record having a plurality of portions wherein each of the plurality of portions corresponds to one of the plurality of transactions, each of said plurality of transaction records comprising at least one changed word having a content and a location therein;
• b. storing said plurality of portions of said audit trail record in a plurality of separate audit trail storage areas, each of said plurality of separate audit trail storage areas being coupled to a corresponding one of said plurality of logical files, each of said plurality of transactions being associated with one of said plurality of logical files and thus being associated with a corresponding one of said plurality of separate audit trail storage areas, said storing step (b) storing each of said plurality of portions of said audit trail record in a corresponding one of said plurality of separate audit trail storage areas;
• c. dumping each of the plurality of logical files to a different one of a plurality of redundant storage facilities before the failure of said at least one of the plurality of logical files, said plurality of redundant storage facilities being coupled to said plurality of logical files;
• and
• d. reconstructing the contents of the at least one of said plurality of logical files after the failure of the at least one of the plurality of logical files using a corresponding one of said plurality of redundant storage facilities and using said corresponding one of said plurality of separate audit trail storage areas.

In a digital data processing system for posting transactions to a data base wherein the data base is stored on a plurality of separate storage elements, the improvement comprising:

• a. generating means for generating transaction records and compiling said transaction records into audit trail data corresponding to each of said transactions;
• b. separating means responsively coupled to said generating means for separating said audit trail data generated for each of said transactions according to a corresponding one of the plurality of separate storage elements;
• c. storing means responsively coupled to said separating means for separately storing said separated audit trail data;
• d. compacting means responsively coupled to said generating means for compacting said audit trail data;
• e. identifying means responsively coupled to said compacting means for identifying changed words within a file of the data base;
• and
• f. index computing means responsively coupled to said identifying means for computing indices within said file of said data base for identifying said changed words.

In a digital data processing system having a plurality of separate storage elements wherein said plurality of separate storage elements store a data base, said digital data processing system posting transactions to the data base, the improvement comprising:

• a. a processor which is programmed for generating a plurality of transaction records and compiling each of said plurality of transaction records into audit trail data corresponding to each of the transactions, each of said plurality of transaction records comprising at least one changed word having a content and a location therein;
• b. a segregating circuit coupled to said processor for segregating said audit trail data prepared for each of the transactions according to a corresponding one of the plurality of separate storage elements;
• c. a plurality of memory elements coupled to said segregating circuit for separately storing the segregated said audit trail data;
• and
• d. said processor further programmed to compact said audit trail data by identifying said at least one changed word within a file of said data base by computing indices of said changed words within said file of said data base.