Under some circumstance it may be neccessary to recreate an instance with out dropping the databases.

Some OS related error is preventing instance start or a connections to a database. Usually this is a SQL1042C error but there can be others. Usually caused by some corrupt or missing file. Can also be caused by file permissions issues.


Use the following steps to drop and recreate the instance with out affecting the databases.

Example:

Assuming the following:
DB2 is installed under: /opt/ibm/db2/V9.7
The instance is named "db2inst1" with a home directory of "/home/db2inst1"

1) Run the following as the instance owner db2inst1 to export the database manager configuration, registry variables and catalog information.

    db2cfexp <output.file>


2) Identify who the fenced user account is by running:

    ls -la /home/db2inst1/sqllib/ctrl/.fencedID

    The owner of this file is the fenced user account.


3) Login as user root and run the following from the /opt/ibm/db2/V9.7/instance path to drop the instance:

    ./db2idrop db2inst1


4) Verify that the instance record is removed by logging in as root and running "/opt/ibm/db2/V9.7/bin/db2greg -dump". A line like this should no longer be displayed

    I,DB2,9.7.0.9,db2inst1,/home/db2inst1/sqllib,,1,0,/opt/ibm/db2/V9.7,,


5) If the above line is still listed, manually remove the old instance from the registry by running the following as root:

    /opt/ibm/db2/V9.7/db2greg -delinstrec service=DB2,instancename=db2inst1


6) Recreate the instance by logging in as root and using the following command from the DB2 install path /opt/ibm/db2/V9.7/instance (assuming the fenced user was identified as "db2fenc1" from step 2):


    ./db2icrt -u db2fenc1 db2inst1


7) Run the following as instance owner db2inst1 to import the database manager configuration, registry variables and catalog information.

    db2cfimp <output.file>



Note: This is for none DPF systems running on UNIX and LINUX operating systems.