[rbldnsd] Problems configuring BIND 9 with rbldnsd

[Michael Tokarev]

Benny Pedersen wrote:
[]
> http://uribl.com/ using gzip compressed zone files to save mirror trafic
> 
> rbldnsd reads dhcp.gz compressed
> 
> so it will be bandwidth saver if the zones could be rsynced in gzip form aswell

Heh.

It's not that simple, really.

With "plain" gzip, rsync will be almost as good as http/ftp/whatever
"plain" download mechanism you use (rsync being an "advanced" mechanism).

Because even very small change in original data changes compressed stream
*alot*, so rsync is just unable to find any unchanged pieces and hence
acts just like plain (but very CPU-hungry) http.

There's a patch for gzip circulating around, that adds --rsyncable option,
so resulting gzip data becomes a bit larger and a bit more rsync-friendly.

But using rsync is useful in the first place only if the data is large and
the changes are small, and even when, good ordering is very important
(and it's not at all obvious what is "good ordering" in this case).

Yes, compressed file d/loaded using http is a big win compared to
uncompressed data over http.  But usage of rsync isn't this simple,
and in many cases (simplistic) rsync approach is more costly than http.

/mjt