Re: [Help-gnunet] files trasnferation rate in local gnunet

[Christian Grothoff]

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On Tuesday 16 December 2003 09:04 pm, YUAN Chao wrote:
> Hi,
>
>   We are consisdering using p2p to sever files in a localized network.
> Becase it's very difficult to maintain a file list database by hand, and
> gnunet seems to be a good candidate for this. Currently we have > 10K
> files with about 100M each stored in ~10 different servers. A simple test
> was made on version 0.6.0 to share one file within a local network.
> However, although we can successfully insert, search and start to d/l
> that file, the transferation speed seems to be limited to about 150kpbs.
> (This was tested on two AMD K&-900 linux box with RH7.3 installed.)
> The speed then became very slow afterward. We are wondering if there's
> some hard-coded limitation in source becase the speed limit in config
> files is already set to a relative high number. Or this is just the
> limitation of the gnunet protocol? I've servey in the mailing-list archive
> and don't know if the previous problem is solved or not.

There are two dominating factors (beyond networking issues that do not matter 
in a LAN) for the speed in your case. First, GNUnet defines 'TTL_DECREMENT', 
a delay for processing messages.  The default value is 5s which is needed for 
anonymity and corresponds to a plausible multiple-hop network-delay on the 
Internet (if you respond after 'about' 5s, it is plausible that you were able 
to communicate with 'anyone' else in the meantime).  For a LAN setting, you 
may want to try 5ms instead -- but be warned, I've never tried this, so you 
may get unexpected results.  

The second, possibly more important factor (especially for large files where 
the 5s don't matter since things are parallelized) is the database. If you 
look on the GNUnet webpage, you will find performance measurements for 
various databases (gdbm, bdb, tdb, mysql, etc.).  150 kbps is about the 
top-speed that most databases support for files encoded with GNUnet's ECRS 
scheme.  So you're likely limited by disk-speed and your choice of database 
at this level.  Try using mysql, which seems to be the fastest DB that we 
currently support.

> BTW, for the testbed mentioned in FAQ, no php3 scripts can be found in the
> source tar ball. Could anyone tell me where it is? Thanks a lot.

There are some php3 scripts in CVS.  Note that testbed is far, far, far from 
finished.  It is among the latest features that are being developed, so it is 
likely to be badly broken.  

Christian
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