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Resource throttling ​

CPU, RAM, IOPS, I/O and Task limits ​

With the release of DirectAdmin 1.61.6, we now support per-user resource throttling.

Requirements ​

The following OS are supported:

  • CentOS 8.x and newer
  • AlmaLinux 8.x and newer
  • RockyLinux 8.x and newer
  • Debian 9.x, 10.x and newer
  • Ubuntu 16.04, 18.04, 20.04 and newer

What does it throttle? ​

  • Cronjobs (Debian systems require session optional pam_systemd.so line to be added to /etc/pam.d/cron)
  • PHP (PHP-FPM, FastCGI) (LSWS and OpenLiteSpeed requires lingering sessions on clients: loginctl enable-linger $USER)
  • Any processes started by the user

What can be throttled? ​

You may control the following options in user package/settings:

  • CPU - percentage of CPU Core, >100% for more than a single cores
  • RAM - hard memory limit for the account
  • IO read/write speeds - max rate data can be read from (or written to) a disk
  • IOPS read/write - max disk read/write operations per second
  • Tasks - max number of tasks user could run

Statistics ​

DirectAdmin shows current resource usage of the user under user-level. Any faults can be also seen on user or admin levels.

What is the difference between CloudLinux and integrated solution? ​

DirectAdmin offers user isolation and resource throttling. CloudLinux offers additional tools like:

  • X-Ray for troubleshooting slow execution of the websites
  • Support end-of-life versions of PHP
  • Ability to control PHP extensions per-user
  • MySQL governor, to throttle MySQL resources (throttles just CPU and read/write bandwidth, because from the technical side it is not possible to throttle other resources due to the use of process threads, that share the memory)

Installation instructions ​

These steps are required for installs of DirectAdmin 1.61.5 and older. Newer versions should have this all done automatically.

It is required to have systemd.unified_cgroup_hierarchy=1 kernel parameter enabled.

If you run OpenVZ/LXC container, you'd need to ask your provider to enable this kernel option for you. Otherwise, just run:

bash
cd /usr/local/directadmin/custombuild
./build grub_conf

If you run debian/ubuntu, we also suggest executing the following, as we've noticed some systems not assigning CPU/IO controllers for user slices:

bash
mkdir -p "/etc/systemd/system/user@.service.d"
echo "[Service]" > "/etc/systemd/system/user@.service.d/delegate.conf"
echo "Delegate=pids memory cpu io" >> "/etc/systemd/system/user@.service.d/delegate.conf"

If it requires to reboot the server after execution grub_conf command - please do.

If you run PHP as FastCGI, Apache needs to be re-installed:

bash
cd /usr/local/directadmin/custombuild
./build apache

If you run PHP as PHP-FPM or lsphp, PHP needs to be re-installed:

bash
cd /usr/local/directadmin/custombuild
./build php

Resource throttling should work successfully now.