differences between freezing vcs system and freezing service group
In veritas vcs, freezing a system prevents service groups from coming online on the system if they failover from another node in the cluster. But this does not prevent faults from failing any service group already online on the system.
To prevent veritas intervention on faults caused by expected changes (even if the symptoms are unexpected) we would usually freeze the service group. This prevents any online/clean or restart operation kicking in on detection of faults.
After your modification on vcs, you need check that resources are not autodisabled and make sure that the config is made ro again.
Here's the step to freeze service group(s) in vcs:
mkdir /var/tmp/veritas_config_backup_`date +%F`
cp -R /etc/VRTSvcs /var/tmp/veritas_config_backup_`date +%F`
/opt/VRTS/bin/hagrp -freeze $i -persistent
/opt/VRTS/bin/haconf -dump -makero