Re: syslog and network management

["Darden, Patrick S." <darden () armc org>]

UDP is a LOT faster than TCP.  No ECC so it uses less cpu, less memory, and has less of a memory footprint.  If you 
were dropping a lot of UDP, then TCP would not help at all--you would receive less, just more reliably.

NG is a great app.  Not sure why it failed you.  Good idea to try a different syslogd.

You state that you switched to regular syslogd with async file io--was the file io set to async with NG also?  If it 
starts happening again try:

vmstat 5 (show disk activity every 5 seconds, io contention, # writes, etc.)
top (let you check cpu activity, ram, top apps, etc.)
sar
netstat -i (check for errors, overruns, and overall activity)

--p

--p

-----Original Message-----
From: firewall-wizards-bounces () listserv icsalabs com
[mailto:firewall-wizards-bounces () listserv icsalabs com]On Behalf Of
david () lang hm
Sent: Saturday, March 01, 2008 2:07 AM
To: Firewall Wizards Security Mailing List
Subject: Re: [fw-wiz] syslog and network management


On Thu, 28 Feb 2008, ArkanoiD wrote:

> Hmm, did you try tcp transport (if your router does support it)?
> It might be better..

the sending devices did not support tcp transport, but there is not much 
of an excuse for a program who's purpose is receiving logs to do so poorly 
at it. if it's missing so many UDP packets that the OS is overflowing it's 
buffers and dropping them than it's going to do bad things to the tcp 
dataflow as well. the difference is that now you are able to rely on the 
sender to act as a buffer as well. but that leaves your logs where you 
don't want them, eating up resources on the sender while being vunerable 
to disruption.

David Lang

> On Tue, Feb 26, 2008 at 02:12:51PM -0800, david () lang hm wrote:
> > > We were logging 6 PIXen as well as many switches and routers (and a
> > > much lesser level). We never "noticed" a great loss of messages... I
> > > guess I can assume you did, and maybe I could learn from how you did!
> > > :)
> > >
> > > What daemon do you use?
> >
> > we tried to use syslog-ng to receive activity from our border router and
> > write a copy locally (in large chunks) and relay the logs to another
> > syslog server inside.
> >
> > we noticed a LOT of missing logs, when we changed to the default debian
> > syslogd we were able to handle an order of magnatude more logs without any
> > sign of missing logs (from around 100/sec to >1000/sec)
>
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