I am worried about having an email server on some OpenVZ VPS. It is too easy to get your files checked and readed by the server admin.
My VPS uses exim4 as MTA, also it uses TLS/SSL to protect against MITM attack, however this all is futile when your service provider can access your private keys files, that are stored in the VPS.
Also, encrypt a disk partition with LUKS won't help, because the server admin could always search of dump throw the RAM memory of the server looking for the point where the information is about the get encrypted, and catch it before that happens.
So, in a general approach, how coul you protect your information on a virtualized platform?
P.S.: please avoid comments like "do you have something to hide?", "why do you want to do this?", "is your information so important?", etc.