iostat and vmstat – Awesome System Statistics for Linux

Published on 2012/09/12, by in linux, sysadmin.




Two excellent Linux apps are iostat and vmstat. These provide realtime statistics of system IO and memory usage. Here’s how it works!




iostat



iostat is useful to view realtime stats of disk IO. I suggest running ‘iostat 1′ to have the command refresh each second.


$ iostat 1
Linux 3.2.0-2-amd64 (brahms) 	09/12/2012 	_x86_64_	(4 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.83    0.16    1.88    0.45    0.00   95.67

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sdb               0.00         0.01         0.00       2220          0
sda               0.00         0.01         0.00       1751         80
sdc               3.38        87.60        34.51   15836593    6238473
sdd               1.60        21.99        28.41    3975881    5136656
sde               0.00         0.01         0.00       2220          0
sdf               8.05       158.58       224.97   28667414   40670076

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.52    2.02   12.63    0.00    0.00   83.84

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sdb               0.00         0.00         0.00          0          0
sda               0.00         0.00         0.00          0          0
sdc               1.00         8.00         0.00          8          0
sdd               0.00         0.00         0.00          0          0
sde               0.00         0.00         0.00          0          0
sdf               0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           2.01    1.51   13.57    0.00    0.00   82.91

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sdb               0.00         0.00         0.00          0          0
sda               0.00         0.00         0.00          0          0
sdc               0.00         0.00         0.00          0          0
sdd               0.00         0.00         0.00          0          0
sde               0.00         0.00         0.00          0          0
sdf               0.00         0.00         0.00          0          0

^C





Another useful option with iostat is tack x to see more detail:

$ iostat -x
Linux 3.2.0-2-amd64 (brahms) 	09/12/2012 	_x86_64_	(4 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.83    0.17    1.88    0.45    0.00   95.67

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sdb               0.00     0.00    0.00    0.00     0.01     0.00     8.24     0.00    0.91    0.91    0.00   0.70   0.00
sda               0.00     0.00    0.00    0.00     0.01     0.00     9.20     0.00    1.15    0.87    8.27   1.15   0.00
sdc               0.06     0.27    2.95    0.43    87.59    34.50    72.18     0.00    1.37    0.46    7.58   0.45   0.15
sdd               0.00     0.43    0.53    1.07    21.99    28.41    63.08     0.09   55.15    5.05   80.00   3.32   0.53
sde               0.00     0.00    0.00    0.00     0.01     0.00     8.24     0.00    0.95    0.95    0.00   0.70   0.00
sdf               0.67     0.56    5.21    2.85   158.55   224.93    95.26     0.15   18.75    3.06   47.44   2.12   1.71





vmstat



Another useful statistic app is vmstat. vmstat stands for virtual memory statistics. Run ‘vmstat 1′ to have this poll every second.

$ vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 2  0   1780 331552  82364 5820336    0    0    68    72    7   37  2  2 96  0
 1  0   1780 331544  82364 5820364    0    0     0     0 3783 2895  2 11 87  0
 1  0   1780 331420  82364 5820364    0    0     0     0 5324 2854  4 12 85  0
 0  0   1780 331296  82364 5820364    0    0     0     0 5355 3386  6 13 81  0
 1  0   1780 331668  82364 5820364    0    0     0     0 4439 3267  6 12 81  0
 1  0   1780 331536  82364 5820364    0    0     0     0 6076 3850  4 12 84  0
 0  0   1780 331136  82364 5820364    0    0     0     0 6165 3146  6 12 83  0
 0  0   1780 331260  82364 5820364    0    0     0     0 3909 2831  2 12 86  0
^C






Cool!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Notify me of followup comments via e-mail. You can also subscribe without commenting.

Home linux iostat and vmstat – Awesome System Statistics for Linux