On Wed, 2004-09-15 at 11:13, Rudi Chiarito wrote:
On Wed, Sep 15, 2004 at 10:43:57AM -0400, Bryan K. Wright wrote:
> directories, though. On my laptop, I have about 20GB of user files
> (images, maps, data, documents) and it takes a few minutes of disk
> grinding for rsync just to walk the tree and decide what's changed.
> This might be prohibitive (or at least prohibitively annoying) for the
> user. It also cuts into the battery life.
Another problem to worry about is saturation of the link upstream. I'm
sure the average user wouldn't want the browser choked by rsync. Yes,
you can tell rsync to use at most N KB/s, but that's not always easy to
get right, if the user is in the position to estimate it at all - not to
mention that link speed might change at any time for e.g. mobile users.
And you run into the risk of the opposite scenario: you are forcing
rsync to use only a fraction of the bandwidth, when there's nothing else
using the rest.
Or do we just assume that there's going to be enough bandwidth? A
saturated DSL is likely to be still more responsive than a saturated 56k
connection.
Well, a bigger problem with rsync is that in many cases, the listing
files part is the biggest time sync. And if that gets interrupted,
you start from the beginning. (*)
So, starting a backup via wireless/vpn when you open your laptop
for 5 minutes at the coffee shop doesn't usually make sense.
So, you might want to look at it as "backup only when on these
networks". I think it's pretty reasonable to assume that people
have lots of bandwidth at home and at work these days.
Regards,
Owen
(*) This may actually not be the case for most people's home
directories; they probably don't have source trees, maildir
folders, etc, so perhaps 200 files is more typical than
the 50,000 you might find in a hacker's homedir.