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I have used I/O stat to check whether my server's I/O is slow or not. The % util is high but so is the read/sec - write/sec. Can anyone help ?

Following is the output of iostat -mx command

Linux 2.6.32-573.12.1.el6.x86_64 (bristol.zcubator.net)     12/14/2017  _x86_64_    (8 CPU)
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           8.60    0.52    2.31   14.94    0.05   73.58
Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
xvdb             10.54   127.57  163.17   18.39     6.23     0.57    76.67     0.83    4.59    3.29   16.13   3.95  71.80
xvdc              0.00     0.00    0.00    0.00     0.00     0.00     8.31     0.00    0.90    0.90    0.00   0.90   0.00
xvda              3.80    20.36   34.52   32.07     0.63     0.43    32.66     0.21    3.09    3.71    2.42   1.16   7.69
BillThor
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badass_programmer
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2 Answers2

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The queue sizes look larger than I would like. You appear to have an unused device, and one very busy device.

The high I/O wait with little CPU activity may indicate that you are paging fairly heavily. This can cause significant performance issues. More memory could help in this case.

BillThor
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Download Netdata and observe the I/O activity in real-time to determine the bottleneck.

ewwhite
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