Send error 55 with vtnet

[fredshed1]

Hi guys,

I've been having problems with my pfSense 2.2 test pair where CARP will automatically demote itself with the following message:
kernel: carp: demoted by 240 to 240 (send error 55 on vtnetX)

where X is the interface number. The machine has 3 vtnet interfaces and this happens on both interfaces using CARP IP addresses (LAN and WAN). The third interface is for pfsync only.

I have worked around the problem by setting the net.inet.carp.senderr_demotion_factor sysctl to 0 which stops the demotion but the errors are still there:
kernel: carp: demoted by 0 to 0 (send error 55 on vtnet0)
The Internet suggests that this may be a problem with mbuf shortages but RRD graphs say only ~5% mbuf usage.

I am worried that this indicates an underlying problem with the network drivers. This system is not heavily loaded - it usually has 4-12mb/s throughput at ~1000pps.

I see this with both pfSense systems in this pair. Both are running in KVM VMs on CentOS 6. One is on HP DL360 G5 hardware, the other HP DL360 G7. Both are now running the latest build of pfSense but this problem has been present for several weeks (perhaps more).

[fredshed1]

This problem is still present on 2.2-RELEASE.