Network unreliable and slow

[freenasadmin12]

Hello,
I have some networking issues and hope to find some help or guidance on what I can check.

With my current build I have the problem that the network sometimes slows down a lot (eg from ~60MiB/s to 1...5 MiB/s writing speed) or doesn't give good speeds at all with some complete timeouts inbetween. This problem seems to affect all network traffic as far as I can tell (SMB, web interface, nextcloud plugin). This is also persistent over multiple updates (just updated from 11.2 to 11.3).

So far I tried different NICs (Intel card vs onboard), different cables and different hosts (linux notebook, android TV box). I looked into /var/log/messages but can't find anything suspicious or fitting the times I notice these problems. Here is how it looks on the UI:

It slows down at 14:40 with some timeouts after 15:05.

The ifconfig output states:

# ifconfig igb0
igb0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=2400b9<RXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,VLAN_HWTSO,RXCSUM_IPV6>
ether 00:25:90:47:5d:78
hwaddr 00:25:90:47:5d:78
inet 192.168.178.177 netmask 0xffffff00 broadcast 192.168.178.255
nd6 options=1<PERFORMNUD>
media: Ethernet autoselect (1000baseT <full-duplex>)
status: active

The used hardware is:
Xeon E3-1230v3, 16GB RAM
Supermicro X10SLL-F
3xWD40EZRZ

Please let me know what else I should check or which data you might need.
Thanks a lot!

 

[Elliot Dierksen]

What kind of hub/switch do you have? I would suggest using iperf to test basic network throughput between devices without disk i/o. The igb type NIC is a well supported one, so I doubt it is that unless it is bad.

 

[freenasadmin12]

Thanks for the super fast reply! I did play a bit with iperf (-i 5 -t 600), it seems I'm still seeing this behaviour:


[ 3] 0.0- 5.0 sec 240 MBytes 402 Mbits/sec
[ 3] 5.0-10.0 sec 827 KBytes 1.36 Mbits/sec
[ 3] 10.0-15.0 sec 0.00 Bytes 0.00 bits/sec
[ 3] 15.0-20.0 sec 0.00 Bytes 0.00 bits/sec
[ 3] 20.0-25.0 sec 172 MBytes 289 Mbits/sec
[ 3] 25.0-30.0 sec 556 MBytes 933 Mbits/sec
...
[ 3] 185.0-190.0 sec 548 MBytes 920 Mbits/sec
[ 3] 190.0-195.0 sec 554 MBytes 929 Mbits/sec
[ 3] 195.0-200.0 sec 549 MBytes 921 Mbits/sec
[ 3] 200.0-205.0 sec 553 MBytes 928 Mbits/sec
[ 3] 205.0-210.0 sec 549 MBytes 921 Mbits/sec
[ 3] 210.0-215.0 sec 392 MBytes 657 Mbits/sec
[ 3] 215.0-220.0 sec 172 MBytes 288 Mbits/sec
[ 3] 220.0-225.0 sec 4.50 MBytes 7.55 Mbits/sec
[ 3] 225.0-230.0 sec 107 MBytes 179 Mbits/sec
[ 3] 230.0-235.0 sec 118 MBytes 197 Mbits/sec
[ 3] 235.0-240.0 sec 109 MBytes 183 Mbits/sec
[ 3] 240.0-245.0 sec 105 MBytes 177 Mbits/sec
[ 3] 245.0-250.0 sec 105 MBytes 177 Mbits/sec
[ 3] 250.0-255.0 sec 105 MBytes 177 Mbits/sec
[ 3] 255.0-260.0 sec 104 MBytes 175 Mbits/sec
...
[ 3] 520.0-525.0 sec 15.0 MBytes 25.1 Mbits/sec
[ 3] 525.0-530.0 sec 0.00 Bytes 0.00 bits/sec
[ 3] 530.0-535.0 sec 0.00 Bytes 0.00 bits/sec
[ 3] 535.0-540.0 sec 0.00 Bytes 0.00 bits/sec
[ 3] 540.0-545.0 sec 487 MBytes 818 Mbits/sec
[ 3] 545.0-550.0 sec 552 MBytes 927 Mbits/sec

The network currently consists of a router (cable router, Vodafone) and all devices connected over LAN. I had the same issues with different options (fritzbox, simple netgear switch).

 

[Elliot Dierksen]

What device(s) do you have besides FreeNAS that can run an iperf server? Do you get the same kind of throughput issues between other devices? It could also be something with the router. You could try a direct cable connection between the FreeNAS and another device. Most gigabit NIC's will do auto mdix meaning you shouldn't need a cross over cable. You need to find different tests until you can isolate the issue to a single component. If I were going to guess, my guess would be either something in the hardware on your FreeNAS or something with the router.

 

[freenasadmin12]

I now tried yet another router and so far it seems to be working really well (consistent >930 Mbit/s). Really strange, as I tried two routers and multiple cables before and the issue persisted. I'll do some further testing but it seems the fault was indeed related to the routers.

Thank you a lot for your help and the fast replies!

 

[Elliot Dierksen]

You are welcome. Glad to hear you isolated the problem.