Master Server runs slower with 1 Slave

Hi, we have a master slave setup version 5.6.22-71_0. The total DB size is 1.1TB, daily data generated is 4GB. The data files are mapped to a SAN using 4 GBit cables. The slave is mapped to the same SAN also, but using only 1 Gbit cable. When we start the slave, in the master some inserts run slower, like some tasks take longer to finish. How can I track what is going on?

move most of the reads to the Slave. Replication impacts the Master in following ways:

  1. Writing to the binlog (disk I/O)
  2. Writing to the slave (via network, presumably Ethernet)