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Unlimited sites on shared hosting: what is really unlimited
«Unlimited websites» in a plan description means exactly one thing: the host doesn't count how many domains and subdomains you add to the account. Everything else — CPU, memory, files, databases, email — still has a ceiling; it just isn't written on the pricing page but in the acceptable use policy and the resource usage section of the panel. That's why hosting with unlimited sites should be chosen not by the headline number but by what's hidden underneath it.
Where the real limits are
On a shared server, each account runs inside a container with limits (most often CloudLinux LVE). All your sites share a single pool of resources:
- CPU and RAM. A fraction of a core or one or two cores and a fixed amount of memory for the whole account. Whether you have one site or forty, when the limit is hit they all slow down at once.
- Processes and I/O. The number of concurrent PHP requests (entry processes) and disk read/write speed are shared too. These are what cause 503 and 508 errors when search engine crawlers hit several sites at the same time.
- Inodes. The file count limit is most often the first real obstacle. A site on a popular CMS with cache and thumbnails easily creates tens of thousands of files, so «unlimited sites» runs into «limited files» somewhere around the second or third dozen projects.
- Databases. Sometimes their number is unlimited too, but the size of a single database and the total volume are capped. The opposite also happens: unlimited sites, but only five or ten databases.
- Email. Mailboxes may be unlimited, but the number of emails per hour is not. Contact forms, notifications and newsletters from all your sites count against one shared limit.
Acceptable use rules
Almost every unlimited plan has a fair use section in the terms of service. It usually says that an account must not consistently use more resources than the server average, that the hosting can't be used as file storage or for backups of other systems, and that hosting third-party sites is only allowed on reseller plans. The host reserves the right to restrict the account or ask you to upgrade. Before buying, find this document and read three points: what counts as overuse, whether you get a warning in advance, and how much time you're given to move.
Also check how inodes and email storage are counted: on some plans, messages in mailboxes count toward the overall disk quota, and a bloated mailbox eats into your sites' space.
Who unlimited sites suit
A plan with no cap on domains is convenient when you have many projects but each of them is light:
- landing pages for ad campaigns and seasonal promotions;
- business card sites, static pages, documentation;
- short-lived test copies and drafts;
- parked domains with a placeholder page or a redirect.
If you have only a few sites and know the list in advance, a plan with a fixed number may be better value for the same resources — compare with the hosting for 10 or more sites selection.
When you need separate accounts
One account means one system user. A vulnerable plugin on an abandoned site gives access to all the neighbouring sites' files, and one heavily loaded page slows the rest down. It's worth splitting sites into separate accounts or plans if:
- the account holds sites belonging to different clients or different companies;
- one project brings in most of your income and can't be put at risk because of the others;
- projects need to run from different IP addresses or at different hosts;
- you need different PHP versions and settings, but the panel only lets you change them for the whole account.
Panels that let you assign a separate user to each site partly solve the isolation problem — for example, hosting with ISPmanager.
When a network of sites should move to a VPS
Shared hosting stays cost-effective while the total load fits within one container's limits. Signs that it's time to change format:
- the panel's resource stats show CPU or processes regularly hitting the ceiling, and upgrading to a bigger plan only helps for a while;
- inodes run out even though there's still plenty of disk space;
- the host has sent you a warning about exceeding the acceptable use rules;
- you need Redis, background workers, long-running cron jobs or your own web server configuration.
On a VPS the resources are reserved for you, there's no file count limit, and sites can be split across users within one panel. Suitable configurations are collected in the VPS for websites selection.