How many websites can be hosted on 4 cores, 16 GB RAM Virtualmin server

Operating system: Debian Linux 10
Hosted at AWS

How many ordinary sites can you run with this:

Apache
Maria DB
Bind
No Dovecot

CPU @ 2.50GHz, 4 cores
16 GB memory
Disk: XXX GB

It’s impossible to calculate this, as it depends on a number of factors, most importantly how the sites are built.

Static HTML sites, thousands.
WP with X amounts of plugins - a bit less.

You will just have to start loading sites on it, and when performance becomes an issue either scale up or start a second server.

2 Likes

See:

How long is a piece of string?

[1]: M 2 = 2 α ′ ( N + N ~ − 2 )

Quite an analogy lol

Thanks @calport and @tpnsolutions
There’s one thing I’m curious about. When creating e.g. student1.domain.com the user becomes “student1” and the home directory “/home/student1”. When I create “domain.com”, the user becomes “domain” and the home directory “/home/domain”.
Is this always correct or can you just as well let the user become “domain.com” and home directory “/home/domain.com”?
Is the efficiency affected depending on which method you use?

I assume from experience that it depends on the type and some other factors like traffic/vistiors (like @toreskev already mentioned).

If you (@ op) provide a few more details, then we could get a more detailed answer.
Most important factors I guess is the cms/language used, the amount of plugins and the visitors/traffic.

Edit:
If I recall correctly, that behavior at the user creation is intended. I could think of multiple reasons for that.

Almost all will have Wordpress est. between 4 and 8 Plugins.
Different Themes also. Not just standard 20, 21.
Normal traffic, not extreme.

@DrCarsonBeckett What if you have both domain1.com and domain1.net with two different sites.
Could you tell me some reasons why you should not have “/home/dom.com” and “dom.com” as user?

The location of the website within the directory structure of /home has no impact on website performance or efficiency, if that is what you were asking.

Wordpress is a resource hog. Big time. You should still be able to run quite a few sites reasonably well, but the problem is that it is so easy for someone to run a bunch of bogus, inefficient, resource hogging plugins that will suck your system dry that it’s bound to end up causing issues eventually.

Are you going to be running all of them yourself or are you going to have different people doing their own thing in each one?

Reason I ask: If you’re doing them all, then go for broke. You will will know when you start to hit your limits.

If it’s going to be others doing their own thing, I would set each VS up with limits so that you’ll know pretty soon who is going to be sucking up all your resources. They’ll start complaining about hitting their limits.

I would actually try to prevent a dot in a username too, but that’s just my guess why it’s not used.
If two users would use the same domain name, but with a different tld then I guess another separator like a number will be added to the name.

In my own experience: I reserve 2GB RAM for the system, so left 14GB RAM If that WP are “normal” with 3000 - 10,000 visitors per month I think you can calculate 1GB per WP site and 2GB per WooCommerce site, BUT like the other guy said: WP is a RAM gobbler… I have a stupid site with TWO pages and almost zero traffic doing 14K queries to the DB per day…
But my advice is: add WP one by one and check stats for some days.