SOLVED During large transfer, speed drops by about 60% and cannot browse web

[oRAirwolf]

I have been working on getting a new NAS going to replace my desktop/consumer hardware NAS with something a little more enterprise grade. My new NAS has the following:

Dell PowerEdge T320 Chassis
Intel Xeon E5-2407 @ 2.20GHz
24GB DDR3 1333 ECC Memory
Broadcom 5720 Dual Port 1Gb integrated NIC
Dell PERC H310 HBA cross flashed to stock LSI firmware in IT mode with these instructions
4 x Seagate 3TB SATA 7200RPM (ST3000DM001-1CH166)

Notes:
Drives are connected to the hot swap SAS backplane of the T320 to the H310
FreeNAS-9.10.2-U3 (e1497f269) installed on 2 x Kingston Data Traveler USB 2.0 drives
System dataset is stored on the USB drives
Using RAIDZ1 striped array with single parity
Autotune enabled under System > Advanced
Both NIC ports connected to HP Procurve 1800-24G (Teaming not enabled)
Router: ASUS RT-AC68P
The Seagate drives are being used for testing the new NAS. Once I feel it is working properly and stable, I will be swapping over my drives from my other FreeNAS box, which has 5 x WD Red NAS 8TB drives
I am testing transfer from my desktop, which has an Intel i218v NIC.

The problem I am running into is when I do a large transfer test from my desktop to the new NAS box. It starts out at a stable ~104MB/s, but eventually will drop all of a sudden to about 41MB/s. Along with the drop in speed, I will no longer be able to access other computers on my network and I cannot surf on the internet from any other device on the network. If I stop the transfer, everything starts working again. I am a little stumped as to what could be causing this. My other NAS is also running the same version of FreeNAS and I can transfer to it all day long with no problems. It is an i7-3770K, 16GB non-ECC, Z68 motherboard, and a PCIe 1GB Intel CT NIC. Does FreeNAS not like those Broadcom 5270 NIC's I have? Any suggestions would be appreciated. I am happy to post any logs I can as well.

 

[SweetAndLow]

Disable auto tune and remove all the tunable that it set. Auto tune should never be used. Disconnect that second nic, one nic on a subnet is best.

Does this happen when you do a single file big transfer? What does iperf show you?

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[m0nkey_]

Autotune enabled under System > Advanced

Turn that off. Delete all the tuneables it created and reboot.

 

[oRAirwolf]

Disable auto tune and remove all the tunable that it set. Auto tune should never be used. Disconnect that second nic, one nic on a subnet is best.

Does this happen when you do a single file big transfer? What does iperf show you?

I disabled autotune, removed all of the tunables it had created, and rebooted. I ran a 20,000 second iperf to the server and it maintained the correct bandwidth. I also created a 1.00 TB dummy file using random data so it was not compressible and moved it to the server. It maintained the same transfer rate the entire time. I think I may be good to go at this point. I had to delete the folder that I previously transferred to make some room, but I will try transferring another folder filled with...ahem...Linux ISO's to see if it works OK as well.

Thanks for your help.

 

[SweetAndLow]

Folders with lots of small files can cause slow downs also.

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[oRAirwolf]

Folders with lots of small files can cause slow downs also.

I moved over about 2.5TB of misc files and it worked fine. I think I'm good to go. Thanks for all the help!