MySql - How to monitor the amount of reads/writes to the DB
In the table GLOBAL_STATUS in information_schema.

Use the field Com_select for reads and sum the fields Com_delete, Com_insert, Com_update, Com_replace for writes.

These values are cumulativ counters, you should subtract values between an interval:

if t1=t0+60seconds, Com_select at t1 - Com_select at t0 = reads in 1 minute