I wanted to experiment with combining bcache and a compressed block device on a hdd and seeing if this will speedup the boot time. Are there any means of compressing a block device at the block level? something like
cloop but with read-write capabilies.
The write need not be very fast. I was thinking of something similar to how the zram deals with it's pages.
I know the future will bring us ubiquitous ssds and stable btrfs with compression, but that really doesn't scratch my itch now :P