no disk io but iowait very high

there is no disk io going results of iotop

Total DISK READ: 0.00 B/s | Total DISK WRITE: 0.00 B/s
  TID  PRIO  USER     DISK READ  DISK WRITE  SWAPIN     IO<    COMMAND
    1 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % init [3]
 1930 be/4 named       0.00 B/s    0.00 B/s  0.00 %  0.00 % named -u ~d/run-root
 1931 be/4 named       0.00 B/s    0.00 B/s  0.00 %  0.00 % named -u ~d/run-root
 1932 be/4 named       0.00 B/s    0.00 B/s  0.00 %  0.00 % named -u ~d/run-root
 1933 be/4 named       0.00 B/s    0.00 B/s  0.00 %  0.00 % named -u ~d/run-root
 1810 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % sh /usr/b~user=mysql
 9795 be/4 apache      0.00 B/s    0.00 B/s  0.00 %  0.00 % httpd
 8004 be/4 apache      0.00 B/s    0.00 B/s  0.00 %  0.00 % httpd
 3226 be/4 postfix     0.00 B/s    0.00 B/s  0.00 %  0.00 % tlsmgr -l -t unix -u
 8154 be/4 apache      0.00 B/s    0.00 B/s  0.00 %  0.00 % httpd
 9759 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % find -name php.ini
 9249 be/4 apache      0.00 B/s    0.00 B/s  0.00 %  0.00 % httpd
 1756 be/4 postfix     0.00 B/s    0.00 B/s  0.00 %  0.00 % psa-pc-re~@localhost
 1863 be/4 mysql       0.00 B/s    0.00 B/s  0.00 %  0.00 % mysqld --~mysql.sock
 3123 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % crond
 1758 be/4 postfix     0.00 B/s    0.00 B/s  0.00 %  0.00 % psa-pc-re~@localhost
 1865 be/4 mysql       0.00 B/s    0.00 B/s  0.00 %  0.00 % mysqld --~mysql.sock
 1592 be/4 sw-cp-se    0.00 B/s    0.00 B/s  0.00 %  0.00 % sw-cp-ser~ver/config
 7612 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % sshd: root@pts/0
 7614 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % sftp-server
 7615 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % -bash
 1602 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % sshd
 8003 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % httpd

but iowait very high ?

iostat report

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.83    0.00    0.13   13.83    0.00   85.20

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn

server runs like a snail what could be wrong here ?

thanks

Solution 1:

iowait can be waiting on anything io related. This includes network, USB, PCI and other devices. Try using iftop to see what your network is doing and consider removing devices from the system.