# Master Server runs slower with 1 Slave

**URL:** <https://forums.percona.com/t/master-server-runs-slower-with-1-slave/4735>\
**Category:** Other MySQL® Questions\
**Created:** [February 19, 2016, 7:05pm UTC](https://forums.percona.com/t/master-server-runs-slower-with-1-slave/4735 "2016-02-19T19:05:35Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Raul\_del\_Cid](https://avatars.discourse-cdn.com/v4/letter/r/c67d28/32.png) [@Raul\_del\_Cid](https://forums.percona.com/u/Raul_del_Cid)\
**Post date:** [February 19, 2016, 7:05pm UTC](https://forums.percona.com/t/master-server-runs-slower-with-1-slave/4735/1 "2016-02-19T19:05:35Z")

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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?

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**Author:** ![JerryZhang](https://avatars.discourse-cdn.com/v4/letter/j/f6c823/32.png) [@JerryZhang](https://forums.percona.com/u/JerryZhang)\
**Post date:** [March 15, 2016, 10:00am UTC](https://forums.percona.com/t/master-server-runs-slower-with-1-slave/4735/2 "2016-03-15T10:00:25Z")

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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)