Linux display disk total statistics including time spent reading and writing data

Posted on in Categories File system, Hardware, Linux, Monitoring last updated January 4, 2008

Most Linux admins are not aware of hidden switch (undocumented switch) called -D. The -D option display a nice summery of disk I/O subsystem since boot time. Output includes total time spent reading and writing data, merged reads and merged writes (kernel disk i/o optimization technique) and other parameters.

vmstat command with -D option

Type the command at shell prompt:
vmstat -D
Output:

           30 disks
            8 partitions
     13739406 total reads
      3887474 merged reads
   1180260353 read sectors
    109630647 milli reading
    118650080 writes
    250115464 merged writes
   2950543038 written sectors
   2382220771 milli writing
            0 inprogress IO
       113832 milli spent IO

This is my local backup server hosted at local data center:
$ uptime
Output:

12:15:07 up 33 days,  9:15,  2 users,  load average: 1.71, 1.49, 1.03

Since last 33 days my server spent total 1180260353 milliseconds reading disk. To get more detailed about disk I/O stats, use the -d option as described in previous article – How do I find out Linux Disk utilization?

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

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