FreeBSD 10.1-REL - network unaccessible after high traffic

[Cs]

It was on 1500 for ~3 years :)

Regards,
Csaba



On May 25, 2015, 10:30, at 10:30, Mark Schouten <mark at tuxis.nl> wrote:
>
>Try lowering your mtu to 1500, that worked miracles for me..
>
>-- 
>Mark Schouten
>Tuxis Internet Engineering
>mark at tuxis.nl / 0318 200208
>
>> On 25 May 2015, at 09:36, "Cs" <bimmer at field.hu> 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 (the problem was the same with cross link too). 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.
>> 
>> 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"
>> 
>> The duplex settings are identical on both servers.
>> 
>> Server A:
>> em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
>9000
>>
>options=4219b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_MAGIC,VLAN_HWTSO>
>
>>        ether 00:25:90:24:52:66
>>        inet x.x.x.x netmask 0xfffffe00 broadcast x.x.x.x
>>        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>>        media: Ethernet autoselect (1000baseT <full-duplex>)
>>        status: active
>> 
>> Server B:
>> em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
>9000
>>
>options=4219b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_MAGIC,VLAN_HWTSO>
>
>>        ether 00:30:48:dd:fe:3e
>>        inet x.x.x.x netmask 0xfffffe00 broadcast x.x.x.x
>>        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>>        media: Ethernet autoselect (1000baseT <full-duplex>)
>>        status: active
>> 
>> Today I tried to set mtu to 9000 but in tcpdump I see that during scp
>it is still 1500:
>>    x.x.x.x.222 > x.x.x.x.37612: Flags [.], cksum 0xb6ee (incorrect ->
>0xda6f), seq 35749, ack 113701596, win 7986, options [nop,nop,TS val
>3103966325 ecr 853712893], length 0
>> 09:27:33.912354 IP (tos 0x8, ttl 64, id 1028, offset 0, flags [DF],
>proto TCP (6), length 1500)
>> 09:27:33.912358 IP (tos 0x8, ttl 64, id 1029, offset 0, flags [DF],
>proto TCP (6), length 1500)
>> 
>> 
>> Any ideas? Thanks guys!
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