Virtualmin is a domain and web hosting software that lets you set up automation tasks and virtualize individual environments for your websites. It is an alternative to cPanel or Plesk, and is based on the Webmin web hosting software.
Virtualmin will run in as little as 512MB of ram with a lot of tweaking, and will run well in 1GB of RAM as long as only a few small websites are being hosted. Virtualmin takes about 20MB of RAM, in addition to Apache’s 100-300MB, MySQL’s 500+MB, and if you’re not using the Cloud DNS manager, BIND can take quite a bit. For a PHP-heavy framework like WordPress, we recommend at least 2GB of ram, especially if using a management panel like Virtualmin. For multiple sites, 4+GB is recommended.
If less than 3GB of ram, use a 32bit OS. This would have to be done manually through an installation ISO as our CentOS + Virtualmnin premade image is x86_64.
Disable Virtualmin pre-loading libraries.
Reduce SpamAssasin and ClamAV
Reduce the number of Apache processes
Remove un-used Apache Modules
Remove un-used services
So, while all of our Linux VPSes will support Virtualmin/Webmin, you may want to do some resource management when using one with less than 2GB of ram.