There is a Percona 5.6.22-71.0 master on SSD on one server and a slave Percona 5.7.22-22 on HDD on another. The base is about 600Gb.
After dumping to the slave, synchronization with the master goes oddly Seconds_Behind_Master then decreases by 1000, then starts to increase by 400. At the same time, Slave_SQL_Running_State: System lock almost constantly. There are no errors, Retrieved_Gtid_Set and Executed_Gtid_Set are changed, iotop does not show a special load - Actual DISK WRITE within 1 Mb / s.
Who faced such strange behavior and how was this problem solved?
PS The option of transferring slave to SSD is not relevant)
