Now testing
(1) delete the file node.log and then reboot, the system generate node.log again, without node.log.archive which might be a backup of node.log
(2)backup the file agreement.cdv and agreement.cdv.archive, then delete them then reboot, the system generate agreement.cdv , without agreement.cdv.archive which might be generated later.
Thinking, maybe it is good to optionally download the log files, or prune them periodically.