[netflow-tools] failed exports

Kevin Wilcox kevin.wilcox at gmail.com
Thu Sep 10 05:23:30 EST 2009

Hi everyone. I'm running softflowd 0.9.8 installed from ports on
FreeBSD 7.2-RELEASE p3.

It is a virtual machine sitting on VMWare ESX using the em device
driver and works great. It collects like a fiend with no lag

My problem is when I issue 'softflowctl statistics'. After having
softflowd running for about 15 minutes and issuing 'softflowctl
statistics' on my busier link, I get:

softflowd[13049]: Accumulated statistics:
Number of active flows: 184115
Packets processed: 27177224
Fragments: 83352
Ignored packets: 27 (27 non-IP, 0 too short)
Flows expired: 289532 (0 forced)
Flows exported: 485703 in 14536 packets (133766 failures)
Packets received by libpcap: 27235906
Packets dropped by libpcap: 58531
Packets dropped by interface: 63

The issue is in the flows reported line, namely the number of
failures. I'm not sure if it's a matter of the send buffer needing to
be increased or, well, what else it could be. I've checked network and
disk utilisation on this machine and the flow collector and all are
well under capacity - if anything, they are minimal usage. All virtual
NICs are gigabit and the physical structure underneath is 100Mb. I'm
about to create dedicated virtual NICs for the flow export so data
never leaves the vswitch but I'm wondering if any of you folks that
are monitoring gigabit links have some advice on where I can look to
find the source of the failures (aside from having my sensor/collector
running on virtual machines)? Scanning the archives has shown some
softflowctl export errors from a few years ago but I get nothing in
syslog about errors...



Whenever there is in any country, uncultivated lands and unemployed
poor, it is clear that the laws of property have been so far extended
as to violate natural right. The earth is given as a common stock for
man to labor and live on. -- Thomas Jefferson, 1785

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