Moved downloads and hg archives to backup server

[Mark Wielaard]

Hi,

Looking at the network stats it seems that since about 5 days ago IcedTea
has suddenly become more than 5 times as popular as before. Probably
because we offered a fix for CVE-2012-4681 in a release very quickly.
Since we were already at network capacity on the main server this pushed
us over the edge.

To make sure we can still keep distributing our work I have redirected
the downloads (http://icedtea.classpath.org/downloads/) and hg archives
(http://icedtea.classpath.org/hg/*/archive/*tar.gz|bz2) to the backup
server. These make up the bulk of the data we distribute.

If I did things correctly things are mostly transparent, downloads
generate a 302 redirect to the backup server. The archives were a bit
tricky though, since we use the SHA256SUMs, they have to be bit-identical
even though they are generated dynamically. I think I got it right.
But it needed the exact same python (2.5) on both servers or some file
ordering got slightly different, causing sha256sum failures.

The backups are generated as soon as possible on every push.
You will notice something like:
  remote: Notifying backup server about /hg/testrepo...
  remote: Scheduled backup of hg/testrepo.
It will then take up to 5 minutes for the hg repo backup to be in sync
with the main server. If anything goes wrong on active push the repos
are also pulled back into sync every 4 hours.

The static download files are synced every 15 minutes. So please be a
little patient when uploading a new release file. It will eventually
show up automagically on the backup server.

Please yell and scream if anything looks wrong.

Apologies for the rush in moving the content, but the sudden large
increase in network traffic really made it necessary.

Thanks,

Mark