For server monitoring I was interested in the log format for Redis. The Redis log format and log levels are not documented so I dug into the source code and this post goes over what I found.
Redis has four log levels: debug, verbose, notice, and warning.
#define LL_DEBUG 0 #define LL_VERBOSE 1 #define LL_NOTICE 2 #define LL_WARNING 3
The notation used in the log is defined as:
const char *c = ".-*#";
The default verbosity log level is notice.
In the log files the various log levels are represented as follows:
Another way to think of it is: dot, line 3 lines, and 4 lines.
The log output for Redis 2.x will look something like this:
[pid] date loglevel message
 14 Nov 07:01:22.119 * Background saving terminated with success
The log output for Redis 3.x changes slightly and adds "role"
pid:role timestamp loglevel message
The possible values for role are as follows:
CRDB/AOF writing child