UDP packet loss

Pavel Urban urbanp at mlp.cz
Thu Jun 8 19:36:41 UTC 2006

Rick Jones wrote:
> Patrick Klos <pklos at osmium.mv.net> wrote:
>> I'd say your biggest problem is the 214 million packet receive
>> errors!  Find the source of those errors, and you'll likely take
>> care of your problem.  Your machine is tossing 1 out of every 4 or 5
>> packets!
> IIRC, 99 times out of 10 those packet receive errors are the socket
> buffer overflowing.
> Now, to actually get a larger socket buffer, you may need to tweak the
> sysctl settings _and_ something in the named config file.  Sysctl to
> raise the limit and named config file to make sure that named doesn't
> "undo" it by asking for something smaller.
> However, that will only help if the issue is occasional bursts of
> requests and the average request rate remains within the limits of the
> server.  If the average request rate is higher than the server can
> satisfy, no increase in the socket buffer will help.
> rick jones

That's what I thought. I just need to know what to change on Bind level. 
Operating system keeps this limit OK, but I don't know if Bind is 
actually using it. I don't think that hardware couldn't keep up with 
traffic (processors are at least 20% idle), about 4GB ram free etc, but 
maybe there is something more to tweak. Suggestions, anyone?


Pavel Urban (pavel.urban at imaginet.cz)
IOL system disaster
Internet OnLine, owned by Cesky Telecom, a.s. (www.ct.cz)
    Vegetables should not operate electronic equipment.
           Computer Stupidities, http://rinkworks.com/stupid/

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