The repair service in OpsCenter will trigger snapshots by default. In some systems this has been seen to cause runaway disk usage.
The user will see a growth in disk usage
The following jira outlines a problem which is influenced by the repair service: https://issues.apache.org/jira/browse/CASSANDRA-9382
1 - On the opscenter machine edit the /etc/opscenter/opscenterd.conf file, add the following at the end:
snapshot_override = False
2 - Restart the opscenter service
sudo service opscenterd restart
Note: from OpsCenter 5.1.2 this setting should be False by default, there is an internal jira open for this under:
OPSC-4692 - "Disable snapshot repair by default in Repair Service"