Scaling up Db2 for Watson Knowledge Catalog

You can run a script to add more memory and CPU to the limited deployment of Db2® service on Cloud Pak for Data to support high-availability or increase processing capacity for the Watson™ Knowledge Catalog service.

Change the scaling configuration for these two instances of Db2u:

iis-db2u
wkc-db2u

Determining if you should scale up Db2 is based on analyzing your monitoring tools (for example grafana graphs) for CPU and memory consumption for the Db2u container. If you observe high CPU throttling or if the container memory is at peak capacity, then you should scale up the instance.

Scale up iis-db2u instance

Complete these steps:

Specify the CPU and memory limit. In this example, CPU is set to 8 vCPU and memory is set to 15 Gi. Modify the values according to your needs.

oc patch db2ucluster db2oltp-iis --type=merge --patch '{"spec": {
"podConfig": {
    "db2u": {
        "resource": {   
            "db2u": {
                "limits": {
                    "cpu": "8",
                    "memory": "15Gi"
                }
            }
        }
    }
}
}}'

Wait for the c-db2oltp-iis-db2u-0 pod to restart.
Exec into the iis-db2u pod:
```
oc exec -it c-db2oltp-iis-db2u-0 -- ksh
```

Create the update_mem.sh script.

cat <<EOF > /db2u/tmp/update_mem.sh
#!/bin/bash
source /etc/profile
source /db2u/scripts/include/common_functions.sh
source /db2u/scripts/include/db2_functions.sh

# Get PID1 environ required for access OS envvar MEMORY_LIMIT
export_pid1_env
source /db2u/scripts/include/db2_memtune_functions.sh

# Deactivate database and stop Db2
db2 terminate
db2 force applications all
db2 deactivate db XMETA
db2 deactivate db IADB
db2 deactivate db DSODB
db2stop force
rah 'ipclean -a'

# Disable remote connections
db2set DB2COMM -null

# Update the normalized instance_memory % value derived from higher MEMORY_LIMIT
rm -f /mnt/blumeta0/SystemConfig/instancememory

# db2start prior to activate db bludb and connection within db2_autoconf.clp
db2start
set_instance_memory
db2stop
db2start

# Re-run autoconfigure to start using updated instance_memory %, and reapply any overrides
run_autoconfigure
apply_cfg_setting_to_db2 "-all"

# Re-enable Db2 remote connections, start Db2 and activate db
db2stop force
rah 'ipclean -a'
db2set DB2COMM=TCPIP,SSL
db2start
db2 activate db XMETA
db2 activate db IADB
db2 activate db DSODB
EOF

Set the execute permission on the update_mem.sh script:
```
chmod +x /db2u/tmp/update_mem.sh
```
Run the script:
```
./db2u/tmp/update_mem.sh
```

Scale up wkc-db2u instance

Complete these steps:

Specify the CPU and memory limit. In this example, CPU is set to 8 vCPU and memory is set to 15 Gi. Modify the values according to your needs.

oc patch db2ucluster db2oltp-wkc --type=merge --patch '{"spec": {
"podConfig": {
    "db2u": {
        "resource": {   
            "db2u": {
                "limits": {
                    "cpu": "8",
                    "memory": "15Gi"
                }
            }
        }
    }
}
}}'

Wait for the c-db2oltp-wkc-db2u-0 pod to restart.
Exec into the wkc-db2u pod:
```
oc exec -it c-db2oltp-wkc-db2u-0 -- ksh
```

Create the update_mem.sh script.

cat <<EOF > /db2u/tmp/update_mem.sh
#!/bin/bash
source /etc/profile
source /db2u/scripts/include/common_functions.sh
source /db2u/scripts/include/db2_functions.sh

# Get PID1 environ required for access OS envvar MEMORY_LIMIT
export_pid1_env
source /db2u/scripts/include/db2_memtune_functions.sh

# Deactivate database and stop Db2
db2 terminate
db2 force applications all
db2 deactivate db ILGDB
db2 deactivate db WFDB
db2 deactivate db BGDB
db2 deactivate db LINEAGE
db2stop force
rah 'ipclean -a'

# Disable remote connections
db2set DB2COMM -null

# Update the normalized instance_memory % value derived from higher MEMORY_LIMIT
rm -f /mnt/blumeta0/SystemConfig/instancememory

# db2start prior to activate db bludb and connection within db2_autoconf.clp
db2start
set_instance_memory
db2stop
db2start

# Re-run autoconfigure to start using updated instance_memory %, and reapply any overrides
run_autoconfigure
apply_cfg_setting_to_db2 "-all"

# Re-enable Db2 remote connections, start Db2 and activate db
db2stop force
rah 'ipclean -a'
db2set DB2COMM=TCPIP,SSL
db2start
db2 activate db ILGDB
db2 activate db WFDB
db2 activate db BGDB
db2 activate db LINEAGE
EOF

Set the execute permission on the update_mem.sh script:
```
chmod +x /db2u/tmp/update_mem.sh
```
Run the script:
```
./db2u/tmp/update_mem.sh
```