Increase of IO delay

[Maher Khalil]

Hello
AS per the attached photo server CPU is maximum 35% while IO delay increased suddenly to reach 26
Any help to understand this
RAM usage reaches 90% of total RAM

 

[Dunuin]

High IO delay = your storage has problems to keep up with the IO.
So you should check if there is a scheduled task that could cause high IO load. Like for example the ZFS scrubing that starts at 00:00.

 

[Maher Khalil]

That happen approximately 23:54:00 up to 00:22
how can I check the schedules tasks?

 

[Maher Khalil]

Could less RAM cause this problem?
my server runs with up to 95% of RAM (waiting for RAM delivery within 2 days)

 

[Maher Khalil]

Here is the daily maximium which says it happens several times per day

 

[Dunuin]

That happen approximately 23:54:00 up to 00:22
how can I check the schedules tasks?

For the host you could look at the "/etc/crontab" and the files in the "/etc/cron.d", "/etc/cron.daily", "/etc/cron.hourly", "/etc/cron.monthly" and "/etc/cron.weekly" folders. But the IO also could come from your guests, so you would need to check them too.

Could less RAM cause this problem?
my server runs with up to 95% of RAM (waiting for RAM delivery within 2 days)

Sure, swapping can cause alot of IO.

 

[Maher Khalil]

So, if it happen from guest. how can I limit it?

 

[Maher Khalil]

io delay in my server dashboard is the same data in disk io in guest dashboard right?
In that case I have to limit guest IO then 1 machine or 2 will not affect my server, right?