Is your site on shared hosting slowing down or showing a 508 or 503 error even though it is quiet? Or did you read "CloudLinux account isolation" on a hosting page and not understand it? This article explains CloudLinux from scratch: what it is, what problem it solves, what limits it puts on your account and how to read them and make use of them.
The takeaway in two lines: CloudLinux is a commercial operating system for hosting servers that isolates each account in a "lightweight virtual environment" (LVE) with set ceilings for processor, memory, disk and processes, and locks every user in a private file "cage" (CageFS). So one over-consuming site cannot stop the server or spy on its neighbors, but you too are bound by your own limits.
📋 Quick summary: CloudLinux in one table
| Term | What it means in simple words |
|---|---|
| CloudLinux OS | A server operating system that follows the RHEL life cycle, built for shared hosting and for dividing resources between accounts |
| LVE | A lightweight virtual environment inside the kernel for each account, with ceilings for processor, memory, disk and processes |
| CageFS | A virtual file system that locks each user in a cage, so they cannot see others or the server's configuration files |
| MySQL Governor | Monitors each user's database use and slows down the queries of anyone going over |
| PHP Selector | Lets the site owner choose the PHP version and its extensions from the control panel |
| Error 508 | Your site has reached its entry process (EP) limit, so your site is slowed without anyone else being affected |
What problem does CloudLinux solve?
In shared hosting, dozens of sites share one processor, memory and disk (for detail read what web hosting is). CloudLinux's documentation says one site can use up the processor, disk, memory or Apache processes and stop the server. Someone who writes a faulty script, whose site is attacked or who hosts huge files harms all their neighbors. The company's fix: put a ceiling on each account that it cannot go past.
How does LVE work?
LVE (Lightweight Virtual Environment) is a technology at the operating system kernel level; the documentation says it has common roots with container virtualization and uses cgroups in its current version, and it is light and transparent. Its stated aim is to guarantee that no site can stop the web server. In practice: the mod_hostinglimits module in Apache checks which site a request came from, puts the Apache process that serves it inside the LVE of that site's user, lets Apache run it, then takes the process out. The kernel makes sure each LVE gets a fair share and does not exceed its limits.
What happens when you reach a limit?
- Processor or disk limit: your site slows down.
- Memory or process-count limit: your visitor sees 500 or 503 errors because the server does not run the script.
- Entry process (EP) limit: the module returns a 508 error, so your heavy site slows and returns 508 errors without anyone else being affected.
HostPapa says CloudLinux isolation runs on all its shared servers and publishes a resource chart for each plan. Essentials is $2.95 a month on a 3-year term and renews at the regular rate
☑️ See HostPapa plans
The limits CloudLinux puts on your account
CloudLinux's documentation defines these limits and their default values in the system (a host may set others for each plan):
| Limit | What it measures | Default value |
|---|---|---|
| SPEED | Processor speed as a share of one core | 100% |
| PMEM | Physical memory (including shared memory and disk cache) | 1024MB |
| IO | Disk read and write speed (read and write together) | 1024KB/s |
| IOPS | The number of read and write operations per second | 1024 |
| NPROC | The maximum number of processes inside the environment | 100 |
| EP (Entry Processes) | Entry processes: usually the maximum number of simultaneous connections to dynamic Apache scripts, plus SSH and cron jobs running at once | 20 |
| Inodes | The number of files and folders in your account (it works at the level of the disk quota) | Set by the host |
The documentation recommends, for an ordinary hosting account, values close to: SPEED 100%, PMEM 1GB, IO 1024KB/s, IOPS 1024, NPROC 100 and EP 20, and for a higher account: SPEED 200%, PMEM 2GB, IO 4096KB/s, NPROC 150 and EP 40. It advises disabling the virtual memory limit (VMEM) because it is deprecated and causes unexpected problems.
A real example: what HostPapa publishes for each plan
The HostPapa plans page says it runs CloudLinux OS on all its shared servers and isolates each account in an LVE that guarantees its resources, and it presents a chart of its limits (values below as read on October 9, 2026; check the live chart before you rely on them):
| Limit | Essentials | Growth | Premium | Elite |
|---|---|---|---|---|
| Entry processes (EP) | 10 | 20 | 40 | 80 |
| CPU cores | 1 | 2 | 4 | 8 |
| Memory | 1,024MB | 1,024MB | 1,024MB | 2,048MB |
| Disk I/O speed | 2,048KB/s | 3,072KB/s | 4,096KB/s | 8,192KB/s |
| Inodes | 150,000 | 300,000 | 450,000 | 600,000 |
| Database size | 500MB | 1GB | 2GB | 4GB |
Notice that memory is the same (1,024MB) in three of the four plans, and what really changes is the number of cores, entry processes and disk speed. If your site gets many simultaneous visits (a store, for example), entry processes are the limit that matters to you. Other hosts publish limits of the same kind, such as Hostinger, whose help center publishes cores, memory, process counts and file counts for each plan, but I could not tell from its page whether it uses CloudLinux.
CloudLinux's main components
CageFS: a cage for each user
A virtual file system that isolates each user in a "cage" holding a fully functional system of their own. The documentation says the user cannot see other users or their names, cannot reach server configuration files such as Apache's, sees a restricted view of /proc so cannot see others' processes, and their environment keeps working without changes to their scripts. It isolates execution through Apache, LiteSpeed, SSH and cron jobs.
MySQL Governor
A tool for monitoring and limiting each user's MySQL use in a shared hosting environment: it tracks processor use and disk reads and writes in real time, and in "abusers" mode it runs the queries of anyone over their limits inside their own LVE so they are slowed. It is not available in the Solo and Admin editions.
PHP Selector
It lets a site owner choose the PHP version they need from many versions with more than 120 extensions, from the hosting control panel (cPanel, Plesk and DirectAdmin). Similar selectors exist for Python, Node.js and Ruby (for cPanel and DirectAdmin servers).
And other tools
Apache mod_lsapi PRO (the company describes it as the fastest PHP handler for Apache), reseller limits to control what each reseller and their customers use, LVE statistics, and site monitoring and slow-site analysis tools in some editions.
CloudLinux OS editions
| Feature | Solo | Admin | Legacy (Shared) | Shared Pro |
|---|---|---|---|---|
| Maximum accounts | 1 | 5 | Unlimited | Unlimited |
| Resource limits (LVE) | Inode limits only | Yes (disabled by default) | Yes | Yes |
| Reseller limits | - | Yes | Yes | No |
| MySQL Governor | No | No | Yes | Yes |
| CageFS and PHP Selector | Yes | Yes | Yes | Yes |
So Solo and Admin are for small servers (a VPS with one or five sites), and Legacy (formerly called Shared) and Shared Pro are for hosts with many sites. The company follows the RHEL life cycle: version 8 ends on May 31, 2029, version 9 on May 31, 2032 and version 10 (released on October 17, 2025) on May 31, 2035 (dates as carried from the original article and RHEL's published lifecycle). It is a commercial license whose price is not shown in the documentation; the host pays it and it is included in your plan's price, and prices vary by edition and number of servers.
What does CloudLinux mean for you as a site owner?
- The plus: your neighbors cannot slow your site by overusing, they cannot see your files and it is hard for one account's errors to spread to the rest of the server.
- The minus: you have a ceiling of your own, so a site that goes over EP or memory is slowed or returns 508 or 503 even though the server itself is not crowded.
- Choice: published limits (like HostPapa's chart) let you compare plans with numbers, not with the phrase "unlimited resources".
- Files: the number of files (inodes) has a ceiling too, and a site with many images, stored mail and backups may reach it before it reaches its space limit.
How do you tell your site is hitting LVE limits? Practical steps
HostPapa shows cores, entry processes, memory, disk speed and inodes for each plan
☑️ See the resource chart
Comparisons: CloudLinux against other ways to isolate
| Option | How it isolates your sites |
|---|---|
| Shared hosting with CloudLinux | A ceiling for each account (LVE) and a file cage (CageFS) on a server many sites share |
| VPS | A virtual machine for you with a system and dedicated resources. You can install CloudLinux on it (Solo for one account and Admin for five accounts) to get CageFS and PHP Selector |
| Managed cloud with containers | Some managed WordPress hosts, such as Kinsta, describe putting each site in its own isolated container; check the provider's own documentation. For the idea read what cloud hosting is |
For VPS detail read what a VPS is, to understand the control panels CloudLinux works with read what cPanel is, and for the meaning of the server itself read what a server is.
Kinsta runs managed WordPress hosting with a WAF, CDN and 24/7 human support on every plan. Launch is $35 a month, or $350 a year
☑️ See Kinsta plans
🎯 Who cares about CloudLinux, and who does not?
✅ It matters to you if:
- Your site is on shared hosting and you run into slowness or 508 and 503 errors
- You compare hosting plans and want numbers, not slogans
- You run a VPS with several sites on it or you sell hosting
- Isolation between sites and stopping neighbors from spying on you matter to you
⚠️ It matters less to you if:
- You use managed container hosting or a dedicated server for your site alone
- You are hosted on a site builder that does not expose the server
- You do not run your own server and have no performance problems
🏆 The final verdict: how do you treat CloudLinux?
CloudLinux protects sites from one another with a ceiling for each account and a cage for each user, and the price is that you have limits of your own that you may reach. So read your plan's limits in numbers (cores, entry processes, memory, disk speed and inodes) before you subscribe, and beware the slogan "unlimited resources". And if you see 508 or 503 errors, check the resource usage page before you blame the server, and lighten your site before you pay for an upgrade.
The chart of cores, entry processes, memory, disk speed and inodes is published for each plan
Start with HostPapa now 🚀
To learn what the file limit (inodes) means, which is enforced at the disk quota level, and how to lower it, read what inodes are.
✅ CloudLinux FAQ
❓ What is CloudLinux?
❓ What is LVE?
❓ What does error 508 mean?
❓ Why do I get 503 or 500 although the server is not crowded?
❓ How do I know whether my hosting uses CloudLinux?
❓ What is CageFS?
❓ What is PHP Selector?
❓ How much does a CloudLinux license cost?
❓ What is the difference between Solo, Admin and Shared Pro?
❓ Can I raise my limits?
❓ Is CloudLinux limited to cPanel?
❓ Does CloudLinux replace security protection?
Cores, entry processes, memory, disk speed and inodes in one chart
☑️ See HostPapa's chart
Have you run into a 508 or 503 error on your hosting? Share in the comments the limit you reached and how you solved the problem.
Related Articles
🖥️ What is cPanel
The control panel CloudLinux works with on shared hosting. Read the guide
🌐 What is web hosting
How sites share one server. Read the guide
🖥️ What is a VPS
A server just for you whose resources you set yourself. Read the guide
☁️ What is cloud hosting
The alternatives: isolation with containers and resources on demand. Read the guide
🗄️ HostPapa hosting review
The plans, the limits and the renewal. Read the HostPapa review
