FreeBSD 10.1-REL - network unaccessible after high traffic

Julian Elischer julian at
Mon May 25 02:31:14 UTC 2015

On 5/24/15 11:12 PM, Cs wrote:
> Hi all,
> I have two FreeBSd 10.1-RELEASE servers connected to each other. 
> They were connected via cross link, but they are connected to a 
> cisco switch now. When transferring huge files (50-500GB backup 
> files) via Gigabit (it is important!) the network randomly dies. The 
> backup runs every day/week and sometimes the connection is ok for 
> months sometimes it happens twice a week. When the network dies I 
> can log in to the server via IPMI and use the console everything is 
> OK, but can't send anything out on the network. ifconfig em0 down/up 
> doesn't help nor netif restart. The problem never occured when I 
> used 100Mbit connection between them, but it was 3com NIC (xl), 
> gigabit adapter is Intel (em0). When I limit the transfer rate 
> (rsync bandwith limit or ipfw pipe) the problem is much more rare.

did you have the problem with no switch?
is he duplex setting correct?

> I tried to set these tuning parameters on both servers with 
> different buffer size but nothing helped:
> # cat /etc/sysctl.conf
> security.bsd.see_other_uids=0
> net.inet.tcp.recvspace=512000
> net.route.netisr_maxqlen=2048
> kern.ipc.nmbclusters=1310720
> net.inet.tcp.sendbuf_max=16777216
> net.inet.tcp.recvbuf_max=16777216
> kern.ipc.soacceptqueue=32768
> # cat /boot/loader.conf
> geom_mirror_load="YES" # RAID1 disk driver (see gmirror(8))
> ipfw_load="YES"
> net.inet.ip.fw.default_to_accept=1
> kern.maxusers=4096
> accf_data_load="YES"
> Any ideas? Thanks guys!
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