What are you using to monitor your services? We're using PRTG with WMI service probes and I get up/down status and response time for the services in PRTG.
Be sure whatever account you're using for the checks has rights to your Pharos server(s).
We saw this exact issue just yesterday, as well as last week. It seems to have started after we updated pserver.exe to 8.2.6005.211. We updated to fix another problem we were having (which has been fixed). We don't see any real symptoms or anything - they just stop working, and we need to restart the database service.
It seems to happen about once a week, on Tuesdays or Wednesdays, so we're having it restart on a schedule to see if this gets around the issue.
We are using Splunk to monitor our services, and we have not been getting warnings when this issue occurs - it has been reported by end userseach time.
With the previous problems, the services would actually stop, and we would be notified by Splunk.