I do not think that ISPConfig v3 is heavy on the resources.
If you do not use certain features, you can switch them off.
Regardless of which control panel you use, the mighty command line is the least resource hungry.
When I had my first experience with ISPConfig, v3 was just introduced. And I installed that instead of v2 as per the tutorial. Not a smart move. Because certain things I wanted to do were not supported yet in v3 then, so I had to uninstall v3, and install v2. I decided not to do this and move on. But that is 1 year ago or so, maybe less or a bit more.
Things will be different now, I'm sure of it.
Try ZPanel v6.1.1 at http://www.zpanelcp.com/
For all Linux incarnations you must have this version, prior to v6.1 Linux was not supported (only Windows Server was).
Next weekend, to try this one out, I will install it in a clone of a template VM with Ubuntu 11.04 Server 64-bit already installed (VMware Workstation).
Or try OpenPanel v1.1 at http://www.openpanel.com/
This is what I started using after ISPConfig, very low resource usage.
And the best is that it has its own CLI, with its own commands. You can even setup and configure Vhosts, DNS, FTP, Quota, email, etc from the CLI and the GUI will pick it all up.
Read the few instructions on the download page.
To keep things lean and mean, you could install just the OS, build-essential, and maybe if you need it OpenSSH (for Putty support), nothing else, and then do an : apt-get install openpanel-minimal
This will install the absolute minimum (see the first screenshot below) to avoid unmet dependencies.
After this, you can pick and choose what plugins you want to install, by first executing an apt-cache search openpanel-mod to list the available OpenPanel modules.
BTW, knock yourself out with all those panels you linked on that page.
I just noticed that something went wrong with the copy+paste of OpenSSL modules above. And I removed that bit.
So now I did a check with apt-get install -suV openpanel-minimal | more
. And the following will get installed for openpanel-minimal :
" in "-suV
" will prevent installation : -s
= No action; perform a simulation of events that would occur but do not actually change the system. )
After installing open-panel minimal you must follow up by installing only those packages you need/want ( with apt-get install ).
These packages are available (some overlap with openpanel-minimal and will already be installed) :