Hello,

Recently I updated my sensors to use PF_RING 5.6.2, after a good long while
on an SVN version of 5.6.1. Initial results on a lightly loaded test box
were good, however when the same setup was loaded onto more heavily loaded
boxes we started seeing a substantial number of dropped packets.

We use the ixgbe PF_RING aware drivers on RHEL 6. The
/proc/net/pf_ring/info reports:

PF_RING Version          : 5.6.2 ($Revision: exported$)
Total rings              : 28

Standard (non DNA) Options
Ring slots               : 16384
Slot version             : 15
Capture TX               : No [RX only]
IP Defragment            : No
Socket Mode              : Standard
Transparent mode         : No [mode 2]
Total plugins            : 0
Cluster Fragment Queue   : 32720
Cluster Fragment Discard : 69173446

The Cluster Fragment Discard numbers are much larger than usual.
Additionally the NIC started reporting drops (less than 1%, but compared to
the previous setup which dropped 0 packets at the NIC). Finally, the snort
and argus processes running on top of this setup now report drops at a much
higher rate than before. Previously snort ran with 1% or less drops, argus
typically dropped only a few thousandths of a percent. Currently, snort is
reporting drops of 15-20%, and argus is seeing roughly 15% drops as well.
This is on a 10 Gb link with peaks of 1.8 Gb/sec with daytime averages of
1.4 Gb/sec. Similar, although smaller, increases in dropped packets was
seen on another link that is much less loaded (300-500 Mb/sec, loss
typically in the 5-10% range).

Overall this is a substantial loss of performance. While I also upgraded
snort and argus to newer versions at the same time as PF_RING, I find it
less likely that both programs made changes to adversely affect packet
capture rates at the same time.

Are there any other reports of this happening? Anything I can do to help
troubleshoot where this packet loss might be happening?

I will file this on the bugzilla as well for tracking.

Cheers,

Jesse

-- 
Jesse Bowling
_______________________________________________
Ntop-misc mailing list
[email protected]
http://listgateway.unipi.it/mailman/listinfo/ntop-misc

Reply via email to