I find that cpview tends to leave about large files. Yesterday I was upgrading a cluster of 3100 appliances and /var/log was filled at 81%
In /var/log/opt/CPshrd-R80.40 there was a bunch of 5 large ond cpview_xxxxxxxxx.dat files. and getting rid of them lowered disk usage in /var./log to 31%
As far as old logs go if your gateway is supposed to send them of to the SmartCenter then any set of log files indicate connectivity iissues where the gateway is unable to send logs to the SmartCenter. If that happens a lot you need to investigate why this happens. As a normal safeguard you should configure logging to forwar live logging but aalso roud up the logs once a day in case stuff gets left behind.
There is a bunch of notes that I must put infto some best practises documents some day. Propably also put it into a nice Ansible playbook as a lot of cleaning up can be automated in my view.
(Just don't hold you breath on it. It's on a too long to-do list.)
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