[clue-tech] "rewindable" drive?

[David L. Willson]

Define "anytime".  Every hour?  Every minute?  :-)

Every moment.  Every write operation logged and time-stamped and the blocks that are replaced by that write operation moved "elsewhere" and stored for "as long as possible", such that the "disk" or filesystem can be rolled back and forth in "time", as long as no new writes occur.  I know this can be done.  I just ~know~ it, Toto.  I mean, Nate.  In fact, I believe that some really smart guy will write not only ~that~, but also the ability to track new writes in a separate branch of the "filesystem-time-line-tree-of-possibility".  Does anyone have contact info for Tom Baker?

I would think your "pause" trick could be used more than once a day, if 
users could handle it, sessions and things are recovering correctly over 
the pause, and the rsync isn't taking too long and timing things out. 
Of course on a day when the dataset changes DRASTICALLY, rsync would 
take too long and you'd have some downtime.  You'd just have to grab a 
stopwatch and see... how long a full sync takes, for example... that's a 
useable baseline...

Suspend, rsync, resume takes 5 minutes, and "Absolutely not!" was the answer to "Is that acceptable?"

I think not only rsync, but something layered over the top of it to get 
time-stamped rsync support (like rdiff-backup) might be good here too, 
if you're already down the rsync path.

I keep hearing rdiff-backup.  Maybe I need to look into that, too.

Volume Shadow Copy is "interesting"... I'm kinda glad I don't really 
have to dig in and find out just HOW "interesting" though.  :-)

I think I'm over-estimating it's capabilities.  IIRC, a VSC unaware app can't be protected by VSC.

Ooh... is this also running on a cluster?  Wicked...

It will be soon.  I'm adding a 3rd VMware Server node and a second storage node, and I'll want the storage nodes to keep their important parts in perfect sync so that my only single point of failure is the network itself, and then I'll start working on that.