Granted Patent B1

US 7,200,626 · App. 10/762,723 · Granted Apr 3, 2007

Abstract

Claims (28)

1. A method for the verification of a quiesced database copy of a primary database by executing a number of independent tasks from an assignment table, said verification to prevent the waste of time during subsequent recovery operations if inaccurate data has been allowed to accumulate, comprising the steps of:

(a) establishing a secondary database copy which replicates said primary database holding data blocks;

(b) quiescing said secondary database copy so that no update access to said database copy is operable;

(c) utilizing a Verify option in a database utility program to check said quiesced secondary database copy for integrity said step including the steps of:

(c1) checking each row in said quiesced database copy to perform a checksum verification;

(c2) checking each row in said quiesced database copy to perform an addresscheck verification;

(d) utilizing a VERIFY TASKS option to control said number of independent tasks assigned to perform said check of said quiesced database copy for integrity.

2. The method of claim 1 which further includes the steps of:

(e) validating the integrity of said secondary database copy by reporting errors that occur during verification;

(f) using the integrity-verified quiesced database copy as a recovery source of data.

3. In a network of multiple processors ( 10 – 13 ) for executing applications and connected to a database system ( 14 ) which utilizes a DM UTILITY program and which operates with a Disk Subsystem ( 22 ) having a primary database ( 15 ) which is duplicated by a disk mirroring system ( 20 ) to a quiesced database copy ( 19 ) which carries a series of data blocks, a system for verifying the integrity of said quiesced database copy ( 19 ) before allowing usage for access, comprising:

(a) means for replicating said primary database ( 15 ) with a quiesced database copy ( 19 );

(b) means to disable access by said applications ( 10 – 13 ) to said quiesced database copy ( 19 );

(c) means to verify the data integrity of said quiesced database copy ( 19 ) including the steps of:

(c1) means to execute a checksum verification of each data block in said database copy ( 19 );

(c2) means to perform an Addresscheck operation on each data block in said quiesced database copy ( 19 );

(d) means to establish data access to said quiesced database copy ( 19 ) after verification of the integrity of said database copy ( 19 ).

4. The system of claim 3 where said means (c) to verify includes:

(sc1) means to check that said duplicated database ( 19 ) is in a state of quiesce;

(sc2) means for accessing an assignment table of tasks required for verification;

(sc3) means for utilizing a Verify database portion of said DMUTILITY program to select tasks to perform verification of each selected data block in said quiesced database copy;

(sc4) means to generate a verification report.

5. The system of claim 4 wherein said means (sc4) to generate a verification report includes:

(sc4a) means to indicate which data blocks were integrity-verified and which blocks were marked as unavailable.

6. The system of claim 5 where said means (sc4a) to indicate includes:

(sc4a1) means to enable further reporting of said database to initiate a repair of said unavailable blocks.

7. The system of claim 5 where said means (sc4a1) includes:

(i) means to mark a checked row with a READERROR in a DISKFILEHEADER if a checksum or addresscheck verification indicated an error.

Assignments (14)