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weird problem.

list Adam Goryachev
Tue, 26 Feb 2013 20:26:47 +1100
Message-Id: <user-e8c7c86067a6@xymon.invalid>

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