We are currently running MySQL 5.1
We use 5 web servers ( Apache ) all connected to 1 DB server ( MySQL ) hosted on the cloud. The DB server running on the cloud ( Master ) replicates to a local DB server ( Slave ) here at our office.
We have noticed when the slave is turned on the masters process list starts loading up with unauthenticated users. Soon as we stop the slave the masters process list slowly goes back down to normal.
RAM/SWAP look fine and there are no slow queries running to explain the buildup in the MySQL process list.
Could this be a network bottleneck? I thought it might be a slow HDD but it doesn't seem to matter what size the bin-log is when its running slow.