SOLVED Low iPerf3 and SMB speeds on TrueNAS Scale

[nimuie]

Hi folks,

long time lurker, first time poster here.

I encountered an issue with a server I built where both SMB and iPerf3 numbers are way lower than expected.

Server:
Motherboard - Supermicro H12SSL-CT
NIC: using the 2 10GbE ports on the motherboard
CPU - EPYC 7443P
SSD: 2 x PCI-e 4.0 Samsung 980 Pro (mirrored)

PC:
classic overspec'ed gaming PC with a 10GbE NIC

Switch
Unifi USW-Aggregation 10GbE

Speeds:
From PC to TrueNAS Scale iPerf3 shows ~4.80 Gbit/sec with SMB speeds of around 450MBps
From TrueNAS scale to PC iPerf3 shows ~ 2.50 Gbit/sec with SMB speeds of around 250MBps

Most posts I was able to find were mentioning either slow SMB speeds but iPerf3 was fine or the opposite. In my case both are bad.

Any thought as to what could cause this and how I could approach solving this issue?

Thanks!

 

[elvisimprsntr]

Are you mixing units? 1Byte = 8bits

Did you enable jumbo frames? MTU=9000

 

[nimuie]

Are you mixing units? 1Byte = 8bits

Did you enable jumbo frames? MTU=9000

Thanks for the reply. As far as I can tell I should be mixing up any units. A 10Gbps connection should realistically deliver around 900-950MBps transfer speeds for files. In my post above I just provided the default that iPerf3 and Windows was showing.

Regarding MTU - where exactly should I change this setting? As it stands on the TrueNAS side I have 2 connections showing the 2 ethernet ports, 1 bond (LACP) which aggregates the 2 and a bride of which the bond is a member of to make VMs work. The bride is the one that has the static IP fixed so should I change the MTU setting for all or just the bridge?

 

[nimuie]

Thanks for the reply. As far as I can tell I should be mixing up any units. A 10Gbps connection should realistically deliver around 900-950MBps transfer speeds for files. In my post above I just provided the default that iPerf3 and Windows was showing.

Regarding MTU - where exactly should I change this setting? As it stands on the TrueNAS side I have 2 connections showing the 2 ethernet ports, 1 bond (LACP) which aggregates the 2 and a bride of which the bond is a member of to make VMs work. The bride is the one that has the static IP fixed so should I change the MTU setting for all or just the bridge?

Look at me learning that this forum doesn't have an edit button.

As far as I can tell I shouldn't* be mixing up any units
a bridge*

Attached a screenshot for clarity

 

[Chris3773]

Right now the speed of Scale is lower then Core, future updates should bring it in line or exceed Core.

I don't know if you have encryption enabled but it was brought up that encryption methods used in Scale may be slower then on Core.


You can change the MTU within Scale by clicking on the interface and updating the MTU to 9000. The bridge should be the one you need to change but it can't hurt to change them all. You will need to change the MTU on your PC and on the switch if it's managed. If it's not managed then it may or may not work.

 

[nimuie]

Ha! Chris3773 and elvisimprsntr you are both stars! Thank you!
After changing the MTU setting on all 3 devices the speed is blasting at 10Gbps.

Writing this down for posterity should other noobs like me face this issue and find this thread:

1. Changed MTU to 9000 in TrueNAS scale for the bride and bond (didn't test if both are needed)
2. Changed MTU to 9000 in Windows using this guide from Microsoft
   1. In my case "Jumbo Frame" doesn't exist. I found "Jumbo Packet" and changed that to "9014 Bytes"
3. Enabled Jumbo Frames on the Unifi Switch using this youtube guide