Linux Command-iotop

Linux Command -- iotop to view CPU usage use top. iotop is required to view I/O usage. This command is added in kernel v2.6.20. Pay attention to the kernel version number during installation. Common iotop Shortcut Keys 1. the left and right arrows --> change the sorting method. The default value is sort by IO. 2. r --> change the sorting order. 3. o --> only processes with IO output are displayed. p --> process/thread display mode switch 5. a --> show cumulative usage 6. q --> Exit 1. install yum install iotop 2. man iotopNAME iotop-simple top-like I/O monitorSYNOPSIS iotop [OPTIONS] DESCRIPTION iotop watches I/O usage information output by the Linux kernel (requires 2.6.20 or later) and displays a table of current I/O usage by processes or threads on the system. at least the CONFIG_TASK_DELAY_ACCT and CONFIG_TASK_IO_ACCOUNTING options need to be enabled in your Linux kernel build configuration, these options depend on CONFIG_TASKSTATS. iotop displays columns for the I/O bandwidth read and written by each process/thread during the sampling period. it also displays the percentage of time the thread/process spent while swapping in and while waiting on I/O. for each process, its I/O priority (class/level) is shown. in addition, the total I/O bandwidth read and written during the sampling period is displayed at the top of the interface. use the left and right arrows to change the sorting, r to reverse the sorting order, o to toggle the -- only option, p to toggle the -- processes option, a to toggle the -- accumulated option, q to quit or I to change the priority of a thread or a process 'thread (s ). any other key will force a refresh. OPTIONS -- version Show the version number and exit-h, -- help Show usage information and exit-o, -- only show processes or threads actually doing I/O, instead of showing all processes or threads. this can be dynamically toggled by press-ing o. -B, -- batch Turn on non-interactive mode. useful for logging I/O usage over time. -n NUM, -- iter = NUM Set the number of iterations before quitting (never quit by default ). this is most useful in non-interactive mode. -d SEC, -- delay = SEC Set the delay between iterations in seconds (1 second by default ). accepts non-integer values such as 1.1 seconds. -p PID, -- pid = pid a list of processes/threads to monitor (all by default ). -u USER, -- user = user a list of users to monitor (all by default)-P, -- processes Only show processes. normally iotop shows all threads. -u USER, -- user = user a list of users to monitor (all by default)-P, -- processes Only show processes. normally iotop shows all threads. -a, -- accumulated Show accumulated I/O instead of bandwidth. in this mode, iotop shows the amount of I/O processes have done since iotop started. -k, -- kilobytes Use kilobytes instead of a human friendly unit. this mode is useful when scripting the batch mode of iotop. instead of choosing the most appropriate unit iotop will display all sizes in kilobytes. -t, -- time Add a timestamp on each line (implies -- batch ). each line will be prefixed by the current time. -q, -- quiet suppress some lines of header (implies -- batch ). this option can be specified up to three times to remove header lines. -q column names are only printed on the first iteration,-qq column names are never printed,-qqq the I/O summary is never printed. see also ionice (1), top (1), vmstat (1) AUTHOR iotop was written by Guillaume Chazarain. this manual page was started by Paul Wise for the Debian project and is placed in the public domain.