If you use plain AES ECB, then little penguins will show up in your encrypted data. You would want to use a disk encryption scheme, like XTS, where the encryption is not just based on the data of the block, but also on the index of the block, to prevent identical blocks at different locations from looking identical. You also want it to be based on a nonce of some sort, to prevent attackers from reverting a block to an older copy.