[GRASS5] grass.itc.it: up again - IP traffic restrictions

[Markus Neteler]

The main site 'grass.itc.it' is up again - the provider
has resolved the network problems.

Some changes:

As the internet traffic consumed nearly all bandwidth of 
our institute, we have activated "apache-throttle" to keep
the maximum traffic below a certain limit over a given period.

If you get a message: 
  "503 - Service temporarily not available"
the server is overloaded. Please use a mirror site close to you.
Probably the "throttle" parameters have to be tuned in a few days.

The current policy is:
- allow 1 Mbit/4sec in general, otherwise "sleep" two seconds
- allow 500Kbit/2sec per IP, otherwise "sleep" two seconds

We have to see how to treat short peaks.


Mirroring with rsync - changes:

Also the mirror sites will be reorganized to use cascaded mirroring. 
rsync connections to grass.itc.it will be only allowed for a few
mirror sites. These mirror sites will provide rsync access for
other mirrors and third party connections.

All changes are needed to reduce the network load here at ITC-irst.

Sorry for any inconvenience,

 Markus Neteler