Setting Resource Limits in Plesk
Resource limits allow you to divide your server into smaller portions that you can then assign to users. This is useful for preventing one website from taking up all the resources on your server, and it comes in handy even if you don't plan to resell hosting. In this section, we will set up our new Hosting Plan to allocate the resources for an average website. Start on the "Resource Limits" tab of the Hosting Plan creation page.
Overuse policy
First, we should consider the overuse policy on our server. It is recommended to disallow overuse unless you are going to be the only person adding sites to the server in order to make it simpler to calculate how many sites can fit. If you leave the default, Plesk will only use the limits you set to calculate how many more sites you can add under a Hosting Plan, though you can have it send you an email if an account goes over the limit. Change the option to "Overuse is not allowed" for now.
Disk space
The most important server resource to set is the disk space, and you should not need to set very much. Unless you have a very media-rich site or lots of email, the vast majority of domains can fit within a single gigabyte of storage, especially if you regularly download your email from the server. This setting controls disk usage for the entire domain, and it is not a hard limit - the customer and the administrator (you) will only be notified that they are approaching the limit for their account. Set the disk space usage to 1GB for this site for now. You may also wish to set the next option to notify you when the account reaches a certain amount of usage before the limit is hit, but it's not truly necessary.
Bandwidth
Next most important is the bandwidth limit. Again, unless your site is very media-heavy, you should not need very much - especially if you are using browser caching. This is a semi-hard limit, which means that Plesk will deactivate any domains that have gone over their bandwidth limit when statistics are run; so, the account can go over, but it will be suspended at some point after that. Since we expect this to be a reasonably text-driven site with an average amount of traffic, we'll this limit to 30GB. You can also set the next option to notify you if you would like to know before the domain will be suspended, but it's not truly necessary in this case.
Domains
You will also need to set the number of domains, subdomains, and domain aliases you would like to allow under the plan. In general, you should not need more than one domain for a small site because each will be given a portion of the disk space. Subdomains can complicate the setup of a domain, and unless you already know you will need them you can disallow them entirely for now by unchecking the "unlimited" box and setting the value to zero. Domain aliases, on the other hand, can be very handy in the case of a WordPress Multi-Site setup and don't take up any extra space on the server, so you can leave the "unlimited" box checked.
Of course, we need to be able to communicate with our visitors, so we'll set a limit of five email addresses at 100MB each. This will allow us to have plenty of space for our site, since mail can only ever use half the available space. We'll disable mailing lists for now (set it to zero) because we won't have a use for one yet. Be aware, however, that this limit is per subscription and not per domain. So, if more than one domain is allowed on a subscription, they will share this limit.
Databases
Next, we'll allow three databases on our account, which should be more than we will need on a simple website. We should only be using one at a time, possibly two, but a third one can be handy if we need to make backups.
Validity period
Finally, we need to give consideration to our "validity period" setting. If you will be the only person creating and managing all accounts under this Reseller Plan, you can set the validity period to "unlimited" so you won't be surprised when your functioning website is suddenly suspended. However, if you expect to be taking payment for sites and want to make sure you do not have customers getting free time on your server without paying, you should set this value to whatever your billing period is, plus any grace period. For now, we'll set this to "unlimited" for the purposes of this tutorial.