Adjust the log level of some logs in the cluster

[enjoy-binbin]

I think the log of pfail status changes will be very useful.
The other parts were scanned and found that it can be modified.

Changes:

1. Changing pfail status releated logs from VERBOSE to NOTICE.
2. Changing configEpoch collision log from VERBOSE(warning) to NOTICE.
3. Changing some logs from DEBUG to NOTICE.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.18%. Comparing base (5d9d418) to head (b045e78).
Report is 7 commits behind head on unstable.

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable     #633      +/-   ##
============================================
- Coverage     70.19%   70.18%   -0.01%     
============================================
  Files           110      110              
  Lines         60049    60077      +28     
============================================
+ Hits          42149    42168      +19     
- Misses        17900    17909       +9     

Files	Coverage Δ
src/cluster_legacy.c	85.92% <100.00%> (+0.30%)	⬆️

... and 20 files with indirect coverage changes

[PingXie]

Thanks @enjoy-binbin! I like these changes. My only question is around when to use NOTICE and when to use WARNING. I would like to see some discussion/clarification on them.

[enjoy-binbin]

My only question is around when to use NOTICE and when to use WARNING. I would like to see some discussion/clarification on them.

i don't have one, maybe madolson has more insight.
currently I am based on experience

[madolson]

i don't have one, maybe madolson has more insight. currently I am based on experience

The previous Redis decision was that LL_WARNING should be for system failures that operators should be notified about and can take action on but shouldn't halt the system (like a serverPanic). LL_NOTICE should be notifications that the average user might want to know about when looking back at the log to understand why something happened (replication disconnects, failovers, elections, etc).