[Xymon] weird problem.

[Adam Goryachev]

On 26/02/13 19:47, Neil Simmonds wrote:
>
> Hi all,
>
>  
>
> I've got a strange problem that I'm trying to diagnose and would
> appreciate any help you can give.
>
>  
>
> We have 2 new servers that have recently been set up that are Aix
> servers running the hobbit client. We have 62 other Aix server with
> the same client running absolutely fine.
>
>  
>
> The problem is that the client data is getting cut off mid stream.
> It's always in the ps output. I've checked the MAX settings and there
> all ok, in fact we have other clients that are sending data files
> larger than these that are working fine. I've checked the data on the
> client and it's complete but if I look in /xymon/data/hostdata on the
> server the data seems to be almost always getting truncated to 69518
> bytes. Occasionally a full message (approx 93k) gets through.
>
>  
>
> There are no messages regarding truncated data in the server logs and
> the only message I can find on the client is the following,
>
>  
>
> 2013-02-26 08:41:21 Write error while sending message to
> bbd at xymonserver:1984
>
> 2013-02-26 08:41:21 Whoops ! bb failed to send message - write error
>
>  
>
> I've googled this extensively and can't find anything that seems
> relevant to our problem.
>
>
I get this from time to time, primarily when the xymon host has very
limited bandwidth. It seems to me that Xymon will accept whatever data
has been received prior to the connection being broken/interrupted, and
pretend it is complete (as opposed to discarding it away).

If this is happening frequently/all the time, I would suspect firewall
settings, and/or MTU issues (if it is packet size related). Check that
you are not blocking all ICMP, or that path MTU discovery is working
properly, check any firewall is not timing out or blocking the
connection for some reason, and that there is enough bandwidth for the
messages.

Potentially, a tcpdump at both client and server could be educational,
possibly load these into wireshark for analysis.

PS, I wonder when we will get compression, and/or encryption for the
status messages? Both would assist in making sure the complete message
arrives un-altered...

Regards,
Adam

-- 
Adam Goryachev
Website Managers
www.websitemanagers.com.au

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