Can I use dd to make a hard drive image onto an NFS share?

I've got a server that currently isn't backed up. It's using about 10GB out of a 40GB hard disk.

I want a way to do periodic disk images while the server is up and running. Acronis Trueimage for Linux is really expensive.

Can I just do something like:

dd if=/dev/dm-1 of=/backup/dm-1.image

Where /backup is on another machine, mounted through NFS?

If so, will it need 40GB space, or just the 10GB that is being used?

Pardon my ignorance.