[hobbit] DNS resolution duration

[Great D Dilla]

As for /etc/resolv.conf, if you have more than 1 DNS servers in the network,
putting the following lines "spreads" the load across the servers:
	option timeout:x (x which is in seconds)
	option rotate (not having to always query the first nameserver, but
to rotate the list)

Afterward check if things improve. It did for me before. 

Of course, having a local caching DNS daemon will be the best solution.

Hope this helps you out.


-----Original Message-----
From: Henrik Stoerner [mailto:henrik at hswn.dk] 
Sent: Wednesday, February 13, 2008 5:45 AM
To: hobbit at hswn.dk
Subject: Re: [hobbit] DNS resolution duration

On Tue, Feb 12, 2008 at 10:52:41AM -0500, Josh Luthman wrote:
> DNS lookups completed                    1202826251.058136
0.072268
> 
> But now when there is a problem reaching the DNS server (I have two in
> /etc/resolv.conf) it spikes up to...
> 
> DNS lookups completed                    1202825989.913910
40.001908
> 
> Is there any way to set the DNS resolution timeout to something
> smaller?  Has anyone tried running bind9 on the Hobbit box itself and
having
> it hold cache locally?  

Hobbit does have a tendency of hitting DNS servers pretty hard. I would
definitely recommend using a local caching DNS server on your Hobbit
box. It is dead simple to setup, and it makes DNS lookups a lot faster
and more reliable.

As far as the timeouts are concerned, the bbtest-net(1) man-page lists
this option:

	--dns-timeout=N (default: 30 seconds)

This assumes you're using Hobbit's built-in resolver library, C-ARES. If
you're running bbtest-net with the --no-ares option, there is no way
Hobbit can control the DNS lookup settings.


Regards,
Henrik


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