Heading up to big PowerDNS recursor deployment
Posted by bert hubert Sat, 25 Mar 2006 15:02:00 GMT
For far too long now we’ve been working on implementing custom features for a big internet service provider here in The Netherlands and it appears we are almost there.
But then again, I’ve thought so a number of times already. The recursor (or resolver) of a network is one of the most crucial components of providing good service.
Put simply, a broken nameserver is perceived as a broken network. A slow nameserver means a slow network. So providers are understandably nervous about migrating to PowerDNS!
Some events may be forcing their hands however. To help ease migration fears, I’ve written dnsreplay_mindex, a tool that replays recorded DNS traffic (which you should anonymise using dnswasher if you plan on shipping it to me!) against PowerDNS, and shows statistics relative to your original nameserver.
I’m now confident that the PowerDNS recursor performs, in many cases, thousands of times better than the competition. Ok, that sentence has a touch of marketing to it. Just a touch. But I’m currently benchmarking at three times the original speed and dropping 30000 times less packets than BIND 8.latest.
That does not mean to say the PowerDNS recursor is perfect. It isn’t, not by a long shot. Even yesterday it turned out one of the more unique features of PowerDNS, the ability to forego hammering broken nameservers with queries that time out, had a cache that was cleaned in reverse: all NEW entries were being removed each minute.
The stunning thing is that it worked fine anyhow, just ate heaps of memory and performed some needless queries - which other nameservers perform all the time in any case.
Furthermore, the recursor carries IP addresses around as full blown strings, for which there is no excuse.
Update: I fixed this here
So there is still work to do, but I’m confident we can migrate at least one of the target servers to PowerDNS on Monday.
In other news, it is a bit quiet on the Niagara (Sun T2000) front, I’m mostly reading up on the unique features of its CPU before delving in with code.
My current aims are to make PowerDNS really fast on T2000 and write a HOWTO about the process, allowing you to benefit from this architecture as well.
On the human interest front, it turns out that leaving the dough to rise in the fridge does indeed produce something that is more like the kind of dough I want, but I’m still not there! I think I’ll aproach my favorite pizza restaurant soon and hope they are willing to share. I already have a proper pizza oven.
I think the traditional way is to add yeast and let it grow at a mild warm temperature, near the heating oven perhaps. I'm lately using beer, it doesn't rise it so much as yeast, but works for slim pizza bases and taco discs.
piotr - that is what I do already, but the dough does not become as elastic as it should be
Prepare it like this: Add white wheat flour to a large enough receptacle, let's say around 400gr, then add one or two teaspoons of salt, I add very fine salt with a grinder. Then dissolve the yeast in a glass of lukewarm water with the fingers, and slowly pour the water into the receptacle while moving it with the hand or a spatule, when all the wheat is humid and forms chunks add one or two spoons of olive oil, which will give the elasticity you need for making a very nice and as thin as you like pizza base. If using beer, substitute water and yeast by beer. After adding the oil the dough needs to be worked until it feels soft and elastic, then, specially if used yeast, let it rest for 20-40 minutes in a warm place (say near the oven) temp should be around 36 degrees, not too much. That should make a good dough, don't forget the olive oil.