[Argus] Re: Packet Loss with racluster

[Nick Diel]

Stew,

I think the first question is what are you using this number for.  If 
you are just using it as an indicator of congestion or other network 
problems then the 5 minute boundary will most likely not be a problem.

I believe Argus just counts the number of retransmitted packets to get a 
loss/drop count, I don't think it is doing any triple duplicate ack or 
tcp timeout checks (if I am wrong, someone please say so).  Since 
retransmissions will occur in a time window of a few seconds, you should 
capture most retransmitted packets in your 5 minute boundaries.  So even 
if a flow cross that boundary, you still have a good chance of counting 
retransmitted packets correctly.

For cases you are receiving a count of 0, I would look at packet rate 
and bit rate, it is possible the link just doesn't have much traffic on 
it at that time. racluster -m proto -s rate load loss -r argus.arg - tcp

Though I did notice something unusual on my end.  The command I gave 
you, should be a strong estimate, but doesn't account for retransmitted 
packets over status flow boundaries within the file (though same 
argument above applies).  So to get an exact count on the file (assuming 
racluster reanalyzes the status flow records for retransmissions) you 
would need something like: racluster -r argus.arg -w - - tcp | racluster 
-m proto -s loss -r - (first merge status flow records, then count 
retransmitted packets).  Though this is the output I get:

racluster -m proto -s loss -r argus.out - tcp
     62521
racluster -r argus.out -w - - tcp | racluster -m proto -s loss -r -
     60047

At a minimum I would expect the numbers to stay the same, no 
retransmitted packets crossed any status flows or racluster doesn't try 
to find any new retransmitted packets.  The number going down doesn't 
make any sense to me.  Maybe someone can explain what is going on to me.

Nick[




Stewart Gray wrote:
> Hey Guys,
>  
> How does racluster handle argus files which have been periodically 
> split, when producing packet loss statistics? My monitoring machine 
> rotates the argus file every 5minutes. When using the following 
> command, how skewed are the figures going to be as a result of having 
> an incomplete argus file (ie connections that were current when the 
> log file was rotated).
>  
> I'm also note than sometimes the resulting figure is 0. It only seems 
> to do this in about 1/10 argus files I run the command at.
>  
> racluster -m proto -s loss -r argus.arg - tcp
> 0
>  
> racluster -m proto -s loss -r argus.arg - tcp
> 33036
> Any ideas?
>  
> Cheers,
>  
> Stew
>
> ------------------------------------------------------------------------
> *From:* Nick Diel [mailto:ndiel at engr.colostate.edu]
> *Sent:* Wednesday, 12 March 2008 10:24 a.m.
> *To:* Stewart Gray
> *Cc:* Argus
> *Subject:* Re: [ARGUS] Cheat sheet premiere
>
> How about:
> racluster -m proto -s loss -r argus.arg - tcp
>
> This should merge all records based on protocol (in this case only tcp 
> because of the filter) and then print the loss column of all merged 
> records.
>
> Nick
>
> Stewart Gray wrote:
>> awesome, That's a really good start. I've already been playing with a 
>> few of the options I hadn't toyed with before :)
>>  
>> Is there an easy way to generate a raw count of packets 
>> loss/retransmitted rather than having it graphed?
>>  
>> I figure we start with:
>>  
>> racluster -s loss -r argus.arg -w -
>>  
>> How are the figured totaled? Do we pipe it to rasort or ra?
>>  
>> Thanks,
>>  
>> Stewart
>>
>> ------------------------------------------------------------------------
>> *From:* Stéphane Peters [mailto:stephane.peters at forem.be]
>> *Sent:* Saturday, 8 March 2008 11:06 a.m.
>> *To:* Carter Bullard
>> *Cc:* Stewart Gray; Argus
>> *Subject:* Re: Re: [ARGUS] Cheat sheet premiere
>>
>> Hi Carter,
>>
>> I would love to see such a sheet in the distribution,
>> and I also was hoping that you could check,
>> if those examples made sense or were appropriate.
>> So please go on !
>>
>>
>> Some cosmetic work could be done too;
>> for example to use everywhere some "standard" parameters like this one :
>>     file=argus-eth1.out
>>     ra -r $file
>> so it is easy to paste the line "as is".
>> without forgetting the shell escapes ( \$srcid) like in:
>>     rasplit -S $argushost  -M 1d -w /path/argus-\$srcid.%Y.%m.%d.log
>>
>> By the way, as another example given to the list, here are 3 scripts 
>> I use.
>> The PATH vars permit to have a nicer ps(1) output.
>>
>> start-argus
>>> #!/bin/sh
>>> interf=eth1
>>> PATH=/sbin ifconfig $interf | grep UP || PATH=/sbin ifconfig $interf up
>>> PATH=/usr/local/sbin argus -d -i $interf -e `hostname` -P 561 -U128 
>>> -mRS 30 -w argus-eth1.out
>>
>> rotate:
>>> #!/bin/sh
>>>
>>> # Rotates server log files, without affecting users who may be
>>> # connected to the server.
>>>
>>> # This can be run as a cron script
>>>
>>> DATE=`date +%Y-%m%d-%H%M`
>>> LOGS='argus-eth1.out'
>>>
>>>  for i in $LOGS; do
>>>    if [ -f $i ]; then
>>>      mv $i $i.$DATE
>>>      gzip -9 $i.$DATE
>>>    fi
>>>  done
>>
>> rotate-daily
>>> #!/bin/sh
>>> ./rotate
>>> sleep 60 # sometimes the preceding command finishes too early
>>> echo ./rotate-daily | at 0000 > /tmp/rotate-daily.log
>>
>> I use at(1) instead of cron(8) to cut the files closer to midnight.,
>> but rastream(1)'s extended "-w" option seems promising.
>> A better solution could be to use argus(8) to preprocess the flows,
>> and rastream(1). to write, "rotate" and compress the files.
>> Another thread, perhaps.
>>
>>
>>
>>
>>
>>    
>>
>>
>> Carter Bullard wrote :
>>> Hey Stephane,
>>> This is great!!!!  I'll put this in the distribution, if you don't 
>>> mind!!!!
>>> And I'll also go through it to make sure that any changes in the
>>> code actually don't break this, and I can add some of the ones
>>> that I do.
>>>
>>> So Russell is asking for a wiki, and we already have one at:
>>>
>>> http://www.vorant.com/nsmwiki/index.php?title=Argus
>>>
>>>
>>> Carter
>>>
>>>
>>>
>>>
>>> On Mar 7, 2008, at 2:24 PM, Stéphane Peters wrote:
>>>
>>>> Hi Stewart,
>>>>
>>>> I also think that a cheat sheet would be nice !
>>>> Here is a good occasion to show mine...
>>>>
>>>> Please note, most of the stuff has been collected right from this 
>>>> argus list,
>>>> so hopefully, you shouldn't browse all the (numerous) past messages.
>>>>
>>>> Any suggestions ?
>>>>
>>>> ------------------------------------------------------------------------
>>>> flow filtering on certain port range:
>>>>    ra -r file - dst port \( gt 1024 and lt 2048 \)
>>>> (...)
>>>> ------------------------------------------------------------------------
>>>>
>>>>
>>>> Stewart Gray a écrit :
>>>>> awesome, that's more like what I was after :) Thanks for your help
>>>>> again. 
>>>>>
>>>>> As I mentioned earlier, I reckon it'd be neat to have some sort of cheat
>>>>> sheet for doing common tasks. I bet there's lot's of stuff you know that
>>>>> others don't, having written the application yourself. I don't know what
>>>>> I don't know!
>>>>>   
>>>>
>>>> Regards,
>>>> -- 
>>>> Stephane.Peters at forem.be, Postmaster at forem.be
>>>
>>
>> Regards,
>> -- 
>> Stephane.Peters at forem.be
>> #####################################################################################
>> Important: This electronic message and attachments (if any) are 
>> confidential and may be legally privileged. If you are not the 
>> intended recipient do not copy, disclose or use the contents in any 
>> way. Please let us know by return e-mail immediately and then destroy 
>> this message.
>> #####################################################################################
>
> #####################################################################################
> Important: This electronic message and attachments (if any) are 
> confidential and may be legally privileged. If you are not the 
> intended recipient do not copy, disclose or use the contents in any 
> way. Please let us know by return e-mail immediately and then destroy 
> this message.
> #####################################################################################

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://pairlist1.pair.net/pipermail/argus/attachments/20080317/5b9fe4c8/attachment.html>