I am trying to achieve "Full Disk Encryption" in a already installed Linux system. I have come across with LUKS with dm-crypt, it can encrypt a drive/entire disk, but before encrypting it is formatting the drive first and all data is getting removed permanently.
As I need to do "Full Disk Encryption" for an existing & mature Linux machine(e.g Ubuntu, centOS), I cannot possibly afford the formatting of the drives/partitions. Is there any possible method by which I can do the "Full Disk Encryption" without loosing the existing contents in the system.
I am very new to these concepts so any proper guidance will be of great help. Thanks!!