Is a journaling filesystem a good idea with a dm-crypt encrypted drive?

Question

I was looking at dm-crypt and have seen that you can use whatever filesystem you like on top of the encrypted drive. So I was wondering if a journaled filesystem is a good idea as opposed to a non-journaled one. Also, what filesystem would be best to deal with power failures with an encrypted drive?

Answer 1

Journaling is a technique that helps with recovery from problems that occur when multi-write operations are interrupted. Such interruptions can leave the file system in an inconsistent state between writes.

Interruptions can happen with "normal" block devices and dm-crypt block devices alike. For a file system, a block device is a block device. Block device encryption and file system journaling are completely separate concerns.

Answer 2

Journaling is orthogonal to encryption. You would run an encrypted device to protect your files private, and you would use a journaling FS to protect the integrity of the data. Given the advancements over the last decade in Linux-based journaling systems, there's really no reason not to use one, except for possibly special scenarios like embedded systems or specially tuned database environments.