[clue-tech] "rewindable" drive?

[David L. Willson]

Do we have constant block-level COW with time-stamping yet?  It's probably obvious from the question, but what I'm looking for is a "rewind-able" filesystem.  Something that time-stamps every changed block every time so that the file-system can be reverted to the state it was in a minute, ten minutes, an hour, or a day ago.  I realize that this would not be appropriate for every job, but it would be appropriate for this job, a small website with a small amount of very valuable data that is highly vulnerable to compromise or inside attack.  In other words, I want to be able to "notice" that my server got cracked a minute, an hour, or a day after the fact, and then "rewind" it to just before the crack happened.

I know the tech is there, with LVM and virt and snapshots but has it been ~done~ yet?