I suspect I'm a bit offtopic with the site mission, but it seems me more fitting for the question than stackoverflow

i'm in preparing to create a vm with sensible data (personal use, it will be a web+mail+... appliance of sorts), i'd like to protect the data even with cryptography; the final choice have to be cross-platform for the host

basically, I have to choose between guest system-level cryptography (say, dm-crypt or similar) or host level cryptography with truecrypt.

do you think that the "truecrypt-volume contained virtualized disks" approach will hit the i/o performance of the vm badly (and therefore dm-crypt like approaches into the vm would be better), or is it doable?

I'd like to protect all the guest data, not only my personal data, to be able to suspend the vm freely without worrying for the swap partition, etc