Migrating the pmcollector

Follow these steps to migrate an old collector node A to a new collector node B. Also, ensure that new collector node provisions sufficient memory and filesystem space. For more information, see Planning for performance monitoring tool for the recommendations.

Install the pmcollector packages on the new node B. Do not start the pmcollector.service on the new node.
Note: If a federation with other collectors is used, the version of the pmcollector package needs to be the same on all the collector nodes that are being used in the federation.
Stop the pmcollector.service on all the collector nodes in the cluster by using the following command:
```
mmdsh -N all systemctl stop pmcollector
```
Disable the service on the old collector node A by using the following command:
```
 systemctl disable pmcollector --now
```
Change the peers section in the /opt/IBM/zimon/ZIMonCollector.cfg file on all the collector nodes so that the new collector node B is included, and the old collector node A is removed.
Note: You must not edit the other collectors in the peers section.
Change the collector setting for the sensor nodes and the perfmon config in CCR by using the following command:
```
mmperfmon config update --collectors=nodeB[,list_of_other_collector_nodes
```
Note:
- Ensure that all used collectors are mentioned in the command.
- Ensure that all nodes in the cluster, especially, the pmsensor nodes of the performance monitoring, can resolve the host names of the newly added collector nodes.
Stop pmcollector.service, and clean the data folder on the new collector node B by using the following commands:
```
systemctl disable pmcollector
systemctl stop pmcollector
rm -r /opt/IBM/zimon/data/*
```
Move the complete data folder with its sub-folders from the old collector node A to the new collector node B by using the following command:
```
scp -r nodeA:/opt/IBM/zimon/data nodeB:/opt/IBM/zimon/
```
Instead of instantly using scp on the node A data folder, you can backup node A and later restore the data on node B by using the tar command.
- To backup the data on node A, use the following command:
```
tar cvPzf /var/tmp/pmcollector-backup.tgz /opt/IBM/zimon/data
```
- To restore the data on node B, use the following command:
```
tar xvPzf /var/tmp/pmcollector-backup.tgz
```
Start the pmcollector.service on the new collector node B by using the following command:
```
systemctl enable pmcollector
systemctl start pmcollector
```
Remove the pmcollector packages on the old collector node A.

Note:

The GUI must have a pmcollector on the same node for performance graphs. You can either move the GUI node along with the pmcollector, or not move the pmcollector.
It is not possible to merge data if data is not collected by the new collector node.