Total DISK READ: 1056.26 K/s | Total DISK WRITE: 9.20 M/s  TID  PRIO  USER     DISK READ  DISK WRITE  SWAPIN     IO>    COMMAND 1055 be/4 root          0.00 B     11.64 M  0.00 %  1.99 % [kjournald] 1054 be/4 root          0.00 B      9.72 M  0.00 %  1.70 % [kjournald] 1053 be/4 root          0.00 B      5.21 M  0.00 %  0.73 % [kjournald] 1056 be/4 root          4.00 K      2.77 M  0.00 %  0.39 % [kjournald] 1082 be/4 root          0.00 B      0.00 B  0.00 %  0.34 % [flush-8:48] 1078 be/4 root          0.00 B      0.00 B  0.00 %  0.33 % [flush-8:32] 1080 be/4 root          0.00 B      0.00 B  0.00 %  0.09 % [flush-8:16]  493 be/3 root          0.00 B   1128.00 K  0.00 %  0.04 % [jbd2/sda3-8] 1081 be/4 root          0.00 B      0.00 B  0.00 %  0.01 % [flush-8:64] 1079 be/4 root         16.00 K    228.00 K  0.00 %  0.01 % [flush-8:0] 1126 be/4 root          0.00 B      0.00 B  0.00 %  0.00 % [kjournald] 1125 be/0 root          0.00 B     56.00 K  0.00 %  0.00 % [loop0] 2974 be/4 nobody        4.00 K     12.00 K  0.00 %  0.00 % httpd -k start -DSSL 5506 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  301 be/4 nobody        0.00 B      8.00 K  0.00 %  0.00 % httpd -k start -DSSL  311 be/4 nobody        0.00 B      8.00 K  0.00 %  0.00 % httpd -k start -DSSL  314 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  332 be/4 nobody        0.00 B      8.00 K  0.00 %  0.00 % httpd -k start -DSSL24916 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  347 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  348 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL16741 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  367 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  368 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  384 be/4 nobody        0.00 B     12.00 K  0.00 %  0.00 % httpd -k start -DSSL  394 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  414 be/4 nobody        0.00 B     12.00 K  0.00 %  0.00 % httpd -k start -DSSL  421 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  422 be/4 nobody        0.00 B      8.00 K  0.00 %  0.00 % httpd -k start -DSSL21049 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL29281 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL29289 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL 3517 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL29389 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL29390 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL29398 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL32207 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSL  874 be/4 nobody        0.00 B      8.00 K  0.00 %  0.00 % httpd -k start -DSSL29562 be/4 nobody        0.00 B      4.00 K  0.00 %  0.00 % httpd -k start -DSSLkjournald writes 11.64 mb data and stuff. THe sum of ALL other writes are not that much. Also what is jbd2/sda3-8
why kjournald uses writes so much?
journaling
You cannot see the real sum of all write from iotop.iotop row number is limited by your terminal height, processes maybe push off the screen by other processes with more recent I/O activities.Processes that wrote to disk then ended will not stay on the list. (eg. httpd spawn/fork process. Base on PID of httpd, I believe many of httpd child process exit already.)Check size of httpd log files, I believe the size should show noticeable increase.JBD2 : http://en.wikipedia.org/wiki/JBD2Overview Quote from wikipedia:The Journaling Block Device (JBD) provides a filesystem-independent interface for filesystem journaling. ext3, ext4 and OCFS2 are known to use JBD. OCFS2 starting from linux 2.6.28 and ext4 use a fork of JBD called JBD2