rrdcached is a daemon that receives updates to existing RRD files, accumulates them and, if enough have been received or a defined time has passed, writes the updates to the RRD file. A flush command may be used to force writing of values to disk, so that graphing facilities and similar can work with up-to-date data.
rrdcached uses the line protocol to communicate with client. When we start rrdcached , it will listen on port 42217 and create a socket file. We can telnet to port 42217 or use ncat to create a connection to socket file.
telnet localhost 42217 or nc -U /var/run/rrdcached/rrdcached.sock
After we connected successfully, we can issue some commands to see what rrdcached is doing.
STATS FLUSHALL
