I’ve been meaning to write about this for a while and since it’s come up recently (Write Intent Bitmaps, Software RAID) I figured now would be a good time. Basically what the write-intent bitmap does is keep track of which blocks are being used so that in the event that a resync is needed (power failure, kernel crash, disk temporarily offline) only the blocks that are out of sync are copied. This drastically improves resync times. Of course there is a downside.

Encryption is becoming more common as users realize the dangers posed if someone were to get the data on their computers. The Ubuntu installer even prompts the user to setup an encrypted disk. While encrypting the primary disk of a desktop or laptop is desirable, I tend to use an external encrypted disk to store much of my data. To be more accurate I create a single large partition on the disk and encrypt that partition. I thought it would be useful, especially given the quality of information on the web, to share my process and some information about the options available.