CPU IOWAIT CRITICAL

Question

I have an error that annoys me enormously because it makes me crash my website at times because the IOWAIT is too high. Here is the mistake I have:

CRITICAL on CPU_IOWAIT (Min:11.3 Mean:14.1 Max:15.7): bioset, bioset, acpi_thermal_pm

when the value is too high I have an ERR_TIMEOUT that appears on my site. Is it possible to fix the problem without changing the machine? Knowing that I have a dedicated server with only 1 website above but with 5 multiboutiques (Prestashop) Thank you for your help.

Solution

This means all your RAM is being used and Linux is using your disk for virtual memory, which is slow and causes iowait because it's waiting on your disk. Prestashop, PHP and MySQL can be configured in many ways that affect performance.

Comments

[Dithers]

Someone might find this thread over at the 'glances' github helpful; github.com/nicolargo/glances/issues/1214

[Chris99391]

the server at 32 GB ram it uses that 3 I have not seen it go above how can I solve this problem? thank you

[Kristopher Ives]

It's possible the database is very poorly optimized and it's doing a lot of table scans. You can run iotop or htop and try to see which processes are causing a heavy IO load.

[Chris99391]

Apparently what takes the most would be [jbd2/md3-8] I do not see what know

[Chris99391]

php-fpm rises at times also not bad

[Kristopher Ives]

Something is causing a large amount of disk activity, probably writing a lot to the disk. You might want to check all logs and how fast they are moving by running find /var/log -name '*.log' | xargs tail -f (as root) but otherwise it's likely a large amount of database activity