"Simple file encryption is useful, but sometimes it's more useful to encrypt a complete filesystem or disk, such as when you need to protect a large set of files. Or you may need not only to protect, but to completely hide the presence of sensitive data from prying eyes. For these cases, here are several options for securing your systems.
"If you have a dedicated encrypted partition or disk, you need to keep only one passphrase or key to unlock all your protected files. Some solutions allow you to go as far as encrypting the swap and the root partition. The drawbacks include sometimes a loss of performance (unfortunately, a necessary trade-off for security), and the fact that if an attacker gets ahold of your key (or you just happen to lose it), you can say goodbye to all your protected files..."
