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:

  • . debug
  • - verbose
  • * notice
  • # warning

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

For instance:
[4018] 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:

  • X sentinel
  • C RDB/AOF writing child
  • S slave
  • M master