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Re: djbdns: An alternative to BIND

  • From: Tobias Reckhard
  • Date: Tue Apr 12 01:52:27 2005 
[email protected] wrote:

A contrary view from the trenches:

Around a year ago we tested DJB dnscache as the recursive DNS server
in a high-volume ISP environment - mostly because we were not happy
with BIND 9 performance at the time. Our conclusions were:

- dnscache used *more* CPU than BIND 9 in our environment, effectively
ruling it out
It'd be interesting to find the actual causes for this. Did you by chance consult the djbdns mailing list for hints?

- Not possible to get dnscache to listen to more than one IP address
unless you introduce hacks/patches
It's easy enough to setup as many instances of dnscache as you have IP addresses and point them all at one central dnscache (typically on a loopback address). Assuming you've already setup the central dnscache, you need to execute the following commands:

# dnscache-conf Gdnscache Ddnslog /etc/dnscacheX a.b.c.d
# echo 127.0.0.1 > /etc/dnscacheX/root/servers/\@
# echo 1 > /etc/dnscacheX/env/FORWARDONLY
# touch /etc/dnscacheX/root/ip/a.b.c
# ln -s /etc/dnscacheX /service

While I agree that it's more work than simply adding one line to a config file, in effect you've got no more than two variables: IP adress, netmask (which I happily assumed to be 255.255.255.0 above). It's trivial to write a script to handle this situation in a one-liner.

Personally, I also like the added flexibility that this approach gives you.

- Weird failures reported from users

Did you actually investigate any of these?


- Annoying installation process with lots of small programs that we
don't want or need
I found the installation process to be relatively straightforward, if a little awkward (as some of DJB's habits are). As for the 'lots of small programs' you don't want or need, I don't see the point. If you install BIND, you get a monolithic binary whereas djbdns splits the functionality into separate programs. Most people only use a fraction of the code in BIND, would you argue that its binary is too large?

[snip]
version that worked well for us (but still too low performance). We
finally switched to Nominum CNS (two servers) and one BIND 9 server
as backup. We really like Nominum CNS, and we're happy.
I've read that Nominum CNS provides good performance. Unfortunately (in my book), it's not Open Source, though.

Cheers,
Tobias