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--- litespeed_wiki:php:server-load-issue [2019/05/14 20:50]
Lisa Clarke Proofreading
+++ litespeed_wiki:php:server-load-issue [2019/06/14 20:04]
Jackson Zhang
@@ Line 8: / Line 8: @@
   * Try to use our [[https://www.litespeedtech.com/products/cache-plugins|LSCache solutions]] to lower the load.
   * It is always good practice to use the ''top'' or ''atop'' command to check which processes are using a lot of CPU resources, and then figure out whether they are behaving normally.
-  * If disk I/O is high, it is likely a disk I/O problem, which you should address. If you have more free memory available, you can move php sessions to ''/dev/shm''.
+  * If disk I/O is high, it is likely a disk I/O problem, which you should address. If you have more free memory available, you can move php sessions to ''/dev/shm''. Disk I/O issue example: <code>top -c</code> iowait ''41.6 wa'' is too high. then check further <code>iostat -x
+Linux 3.10.0-962.3.2.lve1.5.24.10.el7.x86_64 (lbr27.lalunahost.com.br)  04/18/2019      _x86_64_        (8 CPU)
+avg-cpu:  %user   %nice %system %iowait  %steal   %idle
+.65    0.15    2.16   20.24    0.00   70.80
+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               0.16     7.43   16.61    1.80    74.74    78.56    16.65     2.46  133.39    8.38 1284.98   1.45   2.68
+sda              28.25   134.39   93.98   54.24  1445.73  1227.69    36.07     2.11   14.18   46.67   79.17   4.86  72.08</code> ''/dev/sda'' has problem, ''/dev/sdb'' is ok.
   * Check the CPU idle percentage. If it is close to 0%, then your server is CPU-bound and you should try to reduce the CPU usage.
   * When CloudLinux is used, you should try to use the LVE limit to prevent any one user from consuming all of the resources.