[UFO Chicago] Comcast Cuts Off Bandwidth Hogs

[Jordan Bettis]

On Fri, Apr 06, 2007 at 09:17:50AM -0500, Neil R. Ormos wrote:
> 
> There are some interesting incremental backup
> strategies involving rsync and symlinks [1], but
> they usually invert what is ordinarily expected in
> terms of which backup is "complete" and which
> backup is "incremental".  The latest backup is
> "complete" and the prior backups are
> "incremental".  This arrangement works fine if you
> want to keep a complete copy of the original tree
> online, but it is not conducive to saving
> incremental backups to offline media such as tape,
> DVD, CD-ROM.

Right, that's not what I was saying. I was saying you
keep a synchronized copy of the most recent version of
the tree online *only* and then do your incremental
backup onto an off-line medium from that.

That has the advantage of 1) keeping the copy you're
most likely to use online, and 2) using rsync to minimize
bandwidth usage where it's most expensive (across the 
internet).

Something like this:
 
                  |
   primary copy   | foreign host
. . . . . . . . . |. . . . . . .
                  |
    * rsync *     |
    *       *     | internet
  ***       ***   |
    *       *     |
      *   *       |
        *         |
. . . . . . . . . |. . . . . . .
                  |
  on-line copy    | local disc
. . . . . . . . . |. . . . . . .
                  |
    *  tar, *     |
    *  etc  *     | local bus
  ***       ***   |
    *       *     |
      *   *       |
        *         |
. . . . . . . . . |. . . . . . .
                  |
  incremental 2   |
.   .   .   .   . |
                  |  off-line
  incremental 1   |   storage
.   .   .   .   . | (tape, etc)
                  |
   full copy      |
. . . . . . . . . |. . . . . . .


-- 
Jordan Bettis -- Chicago Il.
  <http://neighborhoods.chicago.il.us>                  
    Photographs of Life in the Neighborhoods of Chicago