MySQL Server SWAP usage is high, which causes db to be very slow and slow. mysqlswap

MySQL Server SWAP usage is high, which causes db to be very slow and slow. mysqlswap
High usage of MySQL Server SWAP causes slow db

Environment Introduction:
CentOS: 6.X
MySQL version: 5.5.40
Fault Cause Analysis:
The physical memory is 16 GB, And the swap is 4 GB. MySQL occupies 14 GB of physical memory, while other applications or system processes require 3 GB of memory, at this time, the operating system may map some address spaces owned by MySQL to swap, which may generate swap operation events:

Main causes:
1. mysqldump and mysql import large databases or tables;
2. io writer and io read operations for a large number of concurrent operations at the database layer;
3. copy a large file on the OS layer, such as a database backup file of hundreds of GB.
 
 
Common solution:
1. Release SWAP space
# Swapoff-
Then enable swapon
# Swapon-

2. Add the MySQL Configuration Parameter memlock.
This parameter forces the address space of the mysqld process to be locked in the physical memory.
Set max locked memory
# Echo "mysql hard memlock unlimited">/etc/security/limits. conf
# Echo "mysql soft memlock unlimited">/etc/security/limits. conf

3. Modify Kernel Parameters
# Echo "vm. swappiness = 0">/etc/sysctl. conf

4. Modify the parameters of my. cnf:
Modify the innodb_flush_method parameter in my. cnf to enable the O_DIRECT mode.

5. Use the large page memory.
Reference: http://blog.csdn.net/jacson_bai/article/details/44755109