[clue-tech] "rewindable" drive?

[Collins Richey]

On Wed, Nov 19, 2008 at 11:46 AM, David L. Willson <DLWillson at thegeek.nu> wrote:
> 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.
>

What you need is a Storagetek (now Sun) Iceberg disk system (megabucks
<grin>). The filesystem is designed to allow snapshots, and you can
compare what is changed between the snapshot and current activity. The
key to this is that updated blocks are never written back to the same
spot whence they came. In normal operation, blocks that have been
replaced just become free space that is recaptured by an automatic low
priority process, but if the data has been snapshotted, the original
blocks are retained as part of the snapshot.



-- 
Collins Richey
     If you fill your heart with regrets of yesterday and the worries
     of tomorrow, you have no today to be thankful for.