Question Cache is growing. Server is no longer accessible.

[straddi]

Server operating system version

Debian 12

Plesk version and microupdate number

Plesk Obsidian 18.0.68 Update 2

I hope you can help me.
As the image below shows, my cache is starting to grow and fill up the RAM. This means the server is inaccessible from the outside and essentially shuts down. After a restart, the problem is resolved for a while, but then it starts all over again.
I've already disabled cron jobs and put installed programs into maintenance mode, but that doesn't help.
How can I find out which program is using the cache?
Shouldn't Debian or Plesk solve the problem themselves by freeing up cache for this case?

 

[Sebahat.hadzhi]

Plesk doesn't control the cached memory. It is controlled by the kernel and it should be released should it be needed by another process in the system. I hope that helps:

https://support.plesk.com/hc/en-us/articles/12376921193623-What-does-cached-and-buffered-RAM-mean-in-Plesk-Monitoring-extension

 

[TheHostingHeroes]

Hi

Install plugin Fail2Ban and configure it as it’ll likely be your Plesk login page being attacked which is happening to most Plesk installations.

 

[alvarezcruz]

Cache is not used by programs or processes. It is related to I/O. Linux loads as much I/O data as possible to cache because it's much faster than reading from storage. A lot of cache is normally not a problem and shouldn't bring the system down. The OS should manage it automatically, like you mentioned.

This sounds more like something is taking a massive amount of I/O, which increases cache, and it eventually overloads the server. What's the CPU and disk usage like?