MySQL : Does 'bytes_sent' and 'bytes_received' include mysqldump data?
Do these numbers include mysqldump (backup) data or not ?


It would include mysqldump for one simple reason: It uses a DB Connection. That DB Connection, when you do SHOW PROCESSLIST;, has a SELECT SQL_NO_CACHE running on a table at any given moment during the mysqldump.


  Do they include the log file which is being read by slaves or not?


In MySQL Replication, you have two threads: IO Thread and SQL Thread. They are, for all intents and purposes, DB Connections as they are counted (included) under the global status variable Threads_created. DB Connections and Threads are really one and the same.

What then gets counted?


Bytes sent : IO Thread requesting binlog entries from the Master
Bytes recevied : IO Thread reading binlogs entries from its Master
Bytes recevied : SQL thread reading its own relay logs