On Sun, Jul 25, 2010 at 07:32:54PM +0200, Keld Simonsen wrote:
My machines there are on the Danish research network,
and close to the
Danish Internet exchange (DIX) - some 100 meters from it. We have 10 Gbit
on the university campus, but not (yet) to our machines.
I would think there is good connection
to German research network - I would think it would be a multi gigabit
connection. It should be good for multi 100 mbit/s traffic. - not just 10 Mbit.
Should, yes. In reality it is not.
No, there are
not real limits. In my tests it is possible to get 1
GBit/sec with many machines at the same time.
We are talking about 2 things here:
1. the total bandwidth consumed at a server machine
2. the obtainable bandwidth for an extra machine (a user).
The server is able to provide at least 8 GBit/sec, we tested that. The
university network currently is limited to about 400.000 packets/sec.
Here we still need to experiment. Right now, and I guess all around the
clock, I can get several GBit/sec from the machine when downloading some
file. I don't see when/why this should not be the case (apart from the
2010-07-25 20:05:12 (111 MB/s) - `/dev/null' saved [4697126912/4697126912]
If you find a machine with 10 GBit/sec or more, a decent connection to
our university and the 400kp/s issue is not there, I guess you can
download with 5 GBit/sec and more. I can't test this, though.
Do you get 1 Gbit/s from a testing client machine
towards your server?
Do you get it at this time (Sunday afternoon)?
Yes. I get 1 GBit/sec each for several machines, if I want to. As said,
we reached 8 GBit/sec already.
Hmm, I think you should not try benchmarking from your
machine, it could be that your file systems are very busy.
I think your tests on your own machine was conducted on a client machine?
I downloaded to /dev/null, which is fast. Besides, we have a very fast
file system and a lot of RAM to cache the download. This is clearly not
the issue. The other tests were taken using other machines in the
university, yes. A local download currently gives 8 GBit/sec:
2010-07-25 20:08:15 (1.01 GB/s) - `/dev/null' saved [4697126912/4697126912]
Hmm, how do I control the peer list to be just from
your ftp site?
You don't. Instead you just look at the number for our server and ignore
the others (and the total).
So you are just part of the general opensuse or ubuntu
That should not be too difficult for me to do also.
Yes, that is how BitTorrent works. One huge swarm for a single file.
I don't know how well equipped things are here, I
am not in charge of
routing. Anyway I would expect it to be quite standard, they run a 10 Gbit
backbone at the university campus, and they are hosting the national internet
exchange, wgeer they then also have a number of international lines.
Are you talking about international connection bandwidth?
Yes, since we are in Germany and you are in Denmrak.
I do get fine speeds from other servers in Denmark,
say 200 - 300 Mbit/s.
Denmark is not Germany. Try other servers in Germany. If you can find
_any_ with a decent performance, we can start thinking about problems
at our end.
So you are saying that the bottlenecks are not the ftp
servers, but rather
the national infrastructure, at least in some cases. This could give med
some insights in what mirrors to chose for rsyncing, eg. I should
prefer Danish or Nordic servers to European servers. And BT could also
give and advantage.
This also have inpact on normal users, many users have
20 - 50 - 100 Mbit/s download
connectivity, and having only 10 Mbit/s because of national infrastructure issues
could make the users want to have particular priorities.
I would not say that the connection between Denmark and Germany is 10
MBit/sec. But when you want to download something, you need to think of
So what are the main types of traffic for you? 30 TB a
day is almost
It is. In this case this was the automatic update for Firefox 3.6.7, so
roughly 20% of all (European?) Firefox users downloaded from our server.
This is a lot and in average we had 3 GBit/sec.
Carsten Otto otto(a)informatik.rwth-aachen.de
LuFG Informatik 2 http://verify.rwth-aachen.de/otto/
RWTH Aachen phone: +49 241 80-21211