DB2 instances

DB2 instance is a logical environment for a IBM DB2 database Manager. A physical machine can contain multiple DB2 instances. A DB2 instance can contain multiple databases.

DB2 instance directory contents:

Database Manager Configuration file
System Database Directory
Node Directory
Node Configuration File [db2nodes.cfg] and
Debugging files, dump files

How to create DB2 instance

create a seperate operating system user for the instance you want to create.

useradd -u <ID> -g <group name> -m -d <user location> <user name> 
-p <password>

Go to DB2 instance directory
```
cd /opt/ibm/db2/v10.1/instance 
```

create DB2 instance

./db2icrt -s ese -u <inst id> <instance name>

Verify using list the instances present
```
db2ilist 
```

How to update a DB2 instance

This command is used to update the DB2 instance with same version release.

Note: Stop the instance before updating it

Syntax

#To update the instance in normal mode
db2iupdt <inst_name>

#To update the instance in debugging mode
db2iupdt -D <inst_name>

How to upgrade a DB2 instance

This command is used to upgrade the current version of DB2 instance to a higher version.
Navigate to DB2DIR/instance directory on UNIX/Linux.

Syntax

db2iupgrade -d -k -u <inst_username> <inst_name>

Note:

-d: debbuging mode
-k: to keep the pre-upgrade version in the DB2copy if it's supported.

How to delete a DB2 instance

This command is used to delete a DB2 instance. Navigate to DB2_installation_folder/instance directory on Unix/Linux.

Syntax

db2idrop -u <inst_username> <inst_name>

Commands

Get Instance
This command shows the name of the active DB2 instance.
Syntax
```
db2 get instance 
```
Set Instance
This command is issued to refer the instance name before start or stop of the database manager of a DB2 instance
Syntax
```
set db2instance=<instance_name>
```
Start a DB2 instance
This command is used to start a DB2 instance
Syntax
```
db2start
```
Stop a DB2 instance
This command is used to stop a DB2 instance
Syntax
```
db2stop
```