bind 9.2.1 ON rh9
Mark Andrews
Mark_Andrews at isc.org
Mon Oct 30 23:28:05 UTC 2006
> Mueller, Rex wrote:
> > We need to look into a problem, can you point in a direction in which to
> > look?
> >
> >
> > We are having a problem on a box that acts as our primary DNS machine
> > running Redhat 9.0 and BIND 9.2.1.. Periodically it quits replying to
> > DNS requests, we clear the cache with rndc flush, sometimes, that does
> > not work we have to kill -9 named processes. and restart. Sometimes it
> > hangs and halts the system altogether.
> >
> >
> >
> > I've looked in /var/log/messages there are RRSets and some lameserver
> > entries but we can't seem to isolate what the problem truly is.
> >
> >
> >
> > The hardware is a Dell server, it'd had been working fine for a couple
> > of year and as it was we'd have to rndc flush periodically (once per
> > month..) now it is occuring daily. Sometimes to the point of halting the
> > box. Can't say whether it's hardware or software.
> >
> >
> >
> > Can we put our primary DNS address (via ifconfig) to the secondary and
> > take the primary offline to do hardware diagnostics?
> >
> >
> >
> > At this point we are baffled and need some assistance. Any insight from
> > the group would be greatly appreciated..
> >
> 1. BIND 9.2.1 is pretty old at this point. I'd upgrade that, regardless
> of whether it's the fix to your problem or not.
> 2. If an rndc flush helps some of the time, my knee-jerk reaction is to
> say you're experiencing some sort of memory starvation issue. You didn't
> give any indication of how much memory you have in the box, how much
> named uses typically, query volume/patterns, memory usage statistics
> over a given period of time, etc. so I'm left to reckless speculation on
> that front.
I would say that these represent broken delegations. Something
on the parent side does not match something on the child side.
e.g.
NS RRset and/or address records sets for the nameservers
or NS RRset and/or address records where the nameservers live
or NS RRset and/or address records where the nameservers'
nameservers live
or ...
> 3. If this problem "halts the system altogether", then, my second
> knee-jerk reaction is to say that this goes beyond a mere DNS-software
> problem, and enters the realm of OS (kernel-level) and/or hardware
> problem. Unless perhaps RedHat 9.0 is *really* bad at dealing with
> memory-starvation conditions (in which case it might just be symptomatic).
This sounds like memory starvation though you should get log
messages to that effect.
> 4. Can you migrate the address of your primary DNS server to another
> box, so that you can do diagnostics, without disrupting your clients?
> That's not even really a DNS question. It all depends on your
> LAN/switch/router/firewall configuration/topology. I have no idea what
> devices or paths are used between the clients and servers in your
> network, and what the configurations/rules that those devices might be
> using or not using...
>
>
> - Kevin
>
>
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews at isc.org
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