[Bro] building a new bro server

Gary Faulkner gfaulkner.nsm at gmail.com
Mon Dec 8 16:52:39 PST 2014

A couple thoughts that might help the list better understand your 

 1. Are the manager and/or proxies on the same host?
 2. What are you using to determine packet loss? (ex. Bro capture loss
    script, broctl netstat, pf_ring counters, etc)
 3. Are you running PF_RING using any of the enhanced drivers (DNA/ZC)
    and/or zero copy scripts(Libzero/ZC)?
 4. Are you pinning your worker processes to individual cores (via
    node.cfg) or are you letting the OS handle things?

I saw a marked improvement in average loss as measured by the bro 
capture loss script simply by pinning CPU cores on a server very similar 
to yours with similar traffic per host. Bursty traffic, and mega-flows, 
will still cause higher loss levels for individual workers at times 
though. Also, if you are running the manager and proxies on the same 
host they could be competing for the same cores that one or more workers 
are running on. Running htop might give you an idea of workers are being 
bounced between cores (if not pinned) as well as whether other processes 
are clobbering one or more of the cores your workers are on. Either 
could be an issue with workers running at 100% CPU usage.


On 12/8/2014 4:56 PM, Allen, Brian wrote:
> Hi All-
> I currently have a server running BRO, and we are seeing a lot of 
> packet loss.  I am getting quotes for a new server to replace it, and 
> I wanted to run some of the options by this group to see what would be 
> better.
> Current server specs:
> -2 Processors, 8 cores each at 2.4GHz, so 16 total.  We run 14 bro 
> processes, one per core.  And they run at 100% utilization all the time.
> -128G memory
> -Intel IXGBE 10Gig network card with pfring
> We are seeing 3-4 Gig traffic pretty much constantly, and we spike to 
> 5 Gig.  The bro packet-loss file shows 30+% packet loss most of the 
> time, but during the early morning hours, when traffic drops 
> considerably it will fall to 0.01%.
> For one test, we used a bpf filter to block all traffic going to bro 
> except for a one /24 subnet of campus traffic for about 15 minutes and 
> the packet-loss dropped to 0.01%.
> So we think our processors are too few and too slow to handle this 
> amount of bandwidth.
> Our question as we get a quote to buy a new box is, which is more 
> important for BRO, having the roughly same number of cores but get 
> faster ones, or get more cores at the same or slower speed?
> I’m looking at the following two Dell server options, although I can 
> adjust this to add other better possibilities:
> Option1:
> -Intel Xeon E5-2699, two processors, 18 cores each at 2.3GHz for 36 total
> -256Gig RAM
> -Intel IXGBE 10Gig network card with pfring
> Option2:
> -Intel Xeon E5-2687 two processors, 10 cores each at 3.1GHz for 20 total
> -256Gig RAM
> -Intel IXGBE 10Gig network card with pfring
> I’m assuming the first option would be much better but I’ve never 
> researched this to know for sure, or how much better it would actually 
> be.  I think the difference in price is around $2,400.
> I’d like to get one box to handle our bandwidth as it grows over the 
> next couple years, take the current underpowered box and use it is a 
> BRO test box/elastic search server, and build the infrastructure to 
> move to a BRO cluster in a couple years.  Right now a single box would 
> be better for space issues.
> I would be really interested to talk to other companies/universities 
> who are running bro in the 3-7 Gig bandwidth range right now so I can 
> see what hardware works for you.
> Thanks for your help,
> Brian Allen, CISSP
> Information Security Manager
> Washington University
> brianallen at wustl.edu <mailto:brianallen at wustl.edu>
> 314-935-5380
> _______________________________________________
> Bro mailing list
> bro at bro-ids.org
> http://mailman.ICSI.Berkeley.EDU/mailman/listinfo/bro

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