The 18 GB permanent storage requirement is what Wazuh needs. But doesn’t take into account for the storage requirements for the logging it generates.
In my case, 24 bare metal computers, 40 virtual computers I can barely store all the logging generated in 90 days in the 64 GB of storage assigned to my VM. That won’t be any different for an LXC container.
And even if you have less “machinery” in your environment, logging remains a problem. Especially if there are teens in the household that visit less savory locations on the internet. Because logging is extensive. This is actually a good thing, but take into account that you’ll need much more storage space. Fast.