General :: Encrypting External 4K Sector Drives Correctly

I've recently brought a Western Digital Elements 2TB external hard disk and have been planning to encrypt it for use as a backup drive. However, it seems that these 2TB disks use the new 4K sector sizes and thus need to be handled more carefully than the older 512K ones.

After spending a week looking on Google, I have to admit I'm pretty confused and hope somebody here might be able to verify my conclusions

The drive reports that it's a 512-sector drive which is probably false. Using fdisk -uc, the original partition starts at sector 2048 so I assume that is a valid sector also to start a dm-crypt partition overwriting the previous one?

I've also read that every layer that is added to these drives must support the 4k layer. That means both dm-crypt and the ext3 filesystem I intend to put it on have to do so also.

Looking through the cryptsetup document, it states under the option "--align-payload" the following:

"Align payload at a boundary of value 512-byte sectors. This option is relevant for luksFormat. If your block device lives on a RAID, it is useful to align the filesystem at full stripe boundaries so it can take advantage of the RAIDs geometry. See for instance the sunit and swidth options in the mkfs.xfs manual page. By default, the payload is aligned at an 8 sector (4096 byte) boundary."

The fact that the payload is aligned at 4096 seems to indicate to me that it should be fine using default settings. Does everybody agree with this? Or do I need to take special measures due to the dm-crypt headers?

When I later finish up the dm-crypt layer, then I need to put ext3 on it. I understand adding -b 4096 to the mkfs.ext3 command will resolve that. Is that also correct and will it work well in combination with the dm-crypt layer?