We have about 150-200 users, mostly older people "I click deze icons and dose mails show up" computer illiterates.
EDIT:
I did the following in terminal:
sudo su postgres
psql -c "select * from pg_stat_activity"
see that mess:
Think - "Hell, why not? I'm not in the office tomorrow, so they'll have to live with it if anything goes wrong"
psql -c "select pg_terminate_backend(4536)"
Killed some douchebag query which was hogging the HDD all the time, server load levels went right away back to normal (e.g. to 0.08 from 2.60)
Saved the world, day and my ass since I don't have to move it to a new machine, just backup/clone the drive in Acronis just in case and do zentyal upgrade right away from the webinterface.
Next thing I gotta solve is:
How do i protect this server from spoofing our own emails, like my email is it@domain.com, and i get mails from it@domain.com, also how do i add more sophisticated rules into spamassassin's local.cf and make that actually work, since "module reload just grabs the list of whitelist/blacklist emails and does plain whitelist_from/blacklist_from, where I can use whitelist_from_rcvd or shortcircuiting for lower CPU usage"
But thats another story :3 Thank You all for your help guys!