Re: [Savannah-hackers-public] Setting up bzr+ssh on Savannah.

[Paul Smith]

On Wed, 2010-05-05 at 01:56 -0700, Karl Fogel wrote:
> Karl Fogel <address@hidden> writes:
> >>I'm personaly not so sure about asking people to re-push and such, but
> >>up to you.
> >
> >Well, I'll have to work out the exact recipe, but if people's
> >already-pushed changes are going to disappear, they need to be warned
> >and informed of how to fix it.  I may be able to avoid that by doing the
> >pushes for them, we'll see.
> 
> Turns out we shouldn't have to deal with any re-pushes -- the entire bzr
> repositories all together are around 1.3GB.  We can just go read-only
> long enough to copy that amount over.

For 1.3G it's probably not worth it, but for migrating large data sets I
have found rsync to be invaluable.

What I do is rsync to the new system while everything is still online
and running: for this rsync you don't care whether the result is
coherent or not.  You can continue to do this every so often right up
until the time you want to move (plus this gives you a good feel for how
long the eventual downtime will be).  Then when you're ready you shut
down write access to the data and do a final rsync, which will be very
quick typically since it's only copying the changes since the last
rsync.

Then bring up the service on the new system.

This lets you lock the service from write, and avoid problems with
changes going missing, while still having a quick transition rather than
waiting for all data to copy across.


WFM!  Thanks for all your work on Savannah, folks...