Install LiteSpeed Web Server on DirectAdmin or Plesk

LiteSpeed Web Server Enterprise is a drop-in replacement for Apache: it reads .htaccess and Apache configuration, but serves pages faster with less memory and adds server-level caching (LSCache). This guide covers DirectAdmin and Plesk; for cPanel see install LiteSpeed on cPanel.

Before you start

• A working DirectAdmin or Plesk Obsidian server on AlmaLinux, Rocky, CloudLinux or Ubuntu, fully updated.
• A LiteSpeed Enterprise licence serial number sized for your server (by RAM or worker count), or use a 15-day trial.
• Root SSH access and a fresh backup.
• Background reading: LiteSpeed explained.

DirectAdmin: install with CustomBuild

1. Save your serial so the build can activate it:
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   mkdir -p /usr/local/lsws/conf && echo 'YOUR-SERIAL' > /usr/local/lsws/conf/serial.no

   Use TRIAL in place of the serial for a trial licence.
2. Set LiteSpeed as the web server and use LSAPI for PHP:
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   cd /usr/local/directadmin/custombuild
   ./build set webserver litespeed
   ./build set php1_mode lsphp
   ./build update

3. Build LiteSpeed and rebuild PHP and configs:
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   ./build litespeed
   ./build php
   ./build rewrite_confs

DirectAdmin now shows a LiteSpeed Web Server link at admin level, which opens the LiteSpeed WebAdmin console.

Plesk: install with the LiteSpeed installer

1. Run the LiteSpeed universal installer with your serial (or TRIAL):
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   bash <( curl -s https://get.litespeed.sh ) YOUR-SERIAL

2. The script detects Plesk, installs LiteSpeed alongside Apache and adds the LiteSpeed extension to Plesk.
3. In Plesk open Extensions → LiteSpeed Web Server and click Switch to LiteSpeed. Nginx can stay in front as a proxy or be disabled; LiteSpeed recommends disabling it for best results.

Set the WebAdmin password

Set the admin password for the LiteSpeed console (port 7080):

/usr/local/lsws/admin/misc/admpass.sh

Enable LSCache

LSCache is included in Enterprise. Users enable it per site with the LiteSpeed Cache plugin for WordPress or the modules for other apps; see LiteSpeed Cache for WordPress.

Verify

• Check the server header: curl -I https://example.com should show server: LiteSpeed.
• Check the licence: /usr/local/lsws/bin/lshttpd -V.
• Open a few sites with .htaccess rewrites (WordPress permalinks) and confirm they work.

Roll back to Apache

• DirectAdmin: ./build set webserver apache && ./build set php1_mode php-fpm && ./build apache && ./build php && ./build rewrite_confs
• Plesk: Extensions → LiteSpeed Web Server → Switch to Apache.

Troubleshooting

• Licence error / 503: the serial is not valid for this IP or the worker count is too low; run /usr/local/lsws/bin/lshttpd -r to re-register and check with LiteSpeed.
• PHP errors after switching: rebuild PHP with LSAPI (DirectAdmin) or check the PHP handler in Plesk.
• Some rewrite rules ignored: LiteSpeed supports most Apache rules; complex RewriteMap usage may need changes.

Next steps

• LSAPI PHP explained
• HTTP/3 and QUIC with LiteSpeed
• Update software with CustomBuild