Disk IO constant activity

Hello everyone, I am asking for help from the community because I can not find an explanation for the moment and even after research on this forum I have no answer.

I have a server under proxmox (debian 10) and I am using several LXC containers to act as a web server.

I have containers under apache, others under nginx and more recently under openlitespeed.

Those under apache or nginx have no disk activity except when there is traffic.

On the other hand, those under openlitespeed have a constant disk activity (write) varying from one container to another between 35k and 65k.

I configured the server logs at "warning" level instead of "debug" and I can see that on the dashboard I have a lot less logs, but the disk activity has not changed.

Do any of you have any ideas or at least an explanation?

Thanks a lot for your help.