wrong.
you can have a server with say 1 GB space and 1 GB bandwidth, so you set up pland of 200mb space and 200mb bandwidth which would mean you can place 4 of these on the server as you need to allow the space used for the OS etc.
but if the server is empty then you have not oversold your server becuawe you have not sold anything yet. you would need to sell 5 of these plans to oversell ( as overselling is to oversell available resources) whioch until you sell 5 you have not done.
You don't have to sell anything. Let's be a little more realistic. Suppose you have two identical servers with enough ram and cpu to handle 300 sites. Each server has 500GB of web storage. For the sake of simplicity we'll just discuss overselling and disk space.
Now let us assume that the average web site is about 2GB.
HostA - He does not oversell and offers a 2GB plan. He can sell 250 sites (2gb/plan x 250 plans=500gb)
HostB - He tells himself "I am going to oversell" and so offers a 5GB plan with those same 250 sites. We say he oversells because 5gb/plan x 250 plans = 1,250gb space with only 500GB available (remember, each site is still about 2GB).
And we can say this before he sells his first hosting plan!
So now we have two identical servers: both have 250 sites utilizing the same amount of server resources. The only difference is the hosting plan. Thus you can see its the
HOSTING PLAN not the provisioning that defines overselling. Host B is overselling before he gets his first customer --
by definition
Here is the flipside: both hosts offering a 5GB plan
HostA will not oversell and can sell only 100 plans. HostB can still sell his 250 plans. Thus HostA has 5 servers for every 2 HostB has. Which host can provide the best value? Who's costs will be lower? Who will have the higher revenue?
This also destroys the claim that overselling causes server slowdown. As I mentioned before, and as you can see here, it does not matter how those 250 sites got onto the server -- either PlanA or PlanB -- there will be no difference in server performance.
The question now becomes: Which hosting plan will sell best?