pt工具介绍
Percona Toolkit简称pt工具，是Percona公司开发用于管理MySQL的工具，功能包括检查主从复制的数据一致性、检查重复索引、定位IO占用高的表文件、在线DDL等，DBA熟悉掌握后将极大提高工作效率。

CentOS 7下安装
[root@testdb_172_16_123_101 /root]# yum -y install https://www.percona.com/downloads/percona-toolkit/3.0.1/binary/redhat/7/x86_64/percona-toolkit-3.0.1-1.el7.x86_64.rpm

pt-ioprofile的使用
这个工具可以定位哪个文件IO占用比较高
其原理是对某个pid附加一个strace进程进行IO分析, --profile-pid指定pid, --cell=sizes，该参数将结果已 B/s 的方式展示出来。

[root@testdb_172_16_123_101 /root]# yum -y install strace
[root@testdb_172_16_123_101 /root]# ps aux | grep mysqld
mysql 1962 0.2 21.6 1068008 204420 pts/0 Sl 14:41 0:33 /usr/local/mysql/bin/mysqld --defaults-file=/data/mysql/mysql_3306/my.cnf
root 39205 0.0 0.1 112652 968 pts/0 R+ 18:23 0:00 grep --color=auto mysqld
[root@testdb_172_16_123_101 /root]# pt-ioprofile --profile-pid=1962 --cell=sizes
Mon Apr 10 18:24:00 CST 2017
Tracing process ID 1962
     total       read     pwrite      write      fsync       open      close      lseek  ftruncate filename
   4763136          0    4763136          0          0          0          0          0          0 /data/mysql/mysql_3306/data/ib_logfile0
   4751360          0     163840          0          0          0          0    4587520          0 /data/mysql/mysql_3306/data/db_3306/t1.ibd
   1585066          0          0    1585066          0          0          0          0          0 /data/mysql/mysql_3306/bin_logs/mysql-bin.000009
    802816          0     802816          0          0          0          0          0          0 /data/mysql/mysql_3306/data/ibdata1
    144160     144160          0          0          0          0          0          0          0 /dev/urandom
     15508          0          0       7754          0          0          0       7754          0 /data/mysql/mysql_3306/data/innodb_status.1962
         0          0          0          0          0          0          0          0          0 /data/mysql/mysql_3306/undo_logs/undo003
         0          0          0          0          0          0          0          0          0 /data/mysql/mysql_3306/undo_logs/undo002
         0          0          0          0          0          0          0          0          0 /data/mysql/mysql_3306/undo_logs/undo001
         0          0          0          0          0          0          0          0          0 /data/mysql/mysql_3306/tmp/ibo5OEql