Could nsd handle the future ".eu" ?

Erik Rozendaal erik at
Wed Oct 27 10:15:10 UTC 2004

Stephane Bortzmeyer wrote:
> Opinions ? Facts ?

Here are some of my back-of-the-envelope calculations. Use at your own risk.

As far as NSD scalability is concerned there are three main limitations 
that I'm aware of:

1. Performance

Domain name lookup is O(log N) for N domains. Performance is not 
otherwise affected by the size of the database, so this should not be a 
big scalability limitation.

With large databases zonec and reloads will also take some time.

2. Memory usage.

On a 64-bit machine NSD uses about 100 bytes per RR (based on the .nl 
zone). Memory usage is roughly tripled after signing the .nl zone with a 
1024-bit key. The .nl zone used is rather old and has about 920,000 
delegations and almost 2 million RRs.

3. Internal limitations.

Currently NSD assigns each fully qualified domain name a unique 32-bit 
id. So the maximum number of domain names that NSD can handle is about 
4*10^9 (four billion). I think this is less of a problem than the memory 
usage limitation. This limitation can be removed without too much effort.

Today you can order a four processor AMD Opteron machine with 64 GB of 
memory for roughly $50,000.- from HP.

Assuming you want to do on-the-fly database reloads (instead of 
restarting NSD) you will be able to load about 300 million RRs (NSD 
memory usage will then be about 30 GB). If you don't mind restarts or 
swapping while reloading you can double the number of RRs.

With a four processer system performance should also be very good.

So I'd say .eu could be handled with NSD on current "low-cost" hardware.


More information about the nsd-users mailing list