Tag Archives: smb 3.0 multichannel

Demystifying SMB 3.x multichannel – part 8 – VM1 on Hyper-V host 1 to VM2 on Hyper-V host 2 – 4 NICs in each VM

We are upgrading configuration from previous part (7) so we are adding additional Virtual Network Adapters to both VMs (so each will have 4).

*** When I “hot added” network cards you can see that the throughput was bad (probably we should wait for couple of seconds or minutes for reconfiguration as new network adapters were added) – so on 56th second I am pausing the video for a VMs reboot and on 58th second I am resuming recording after VMs reboot. You can see that after reboot everything works great and we are getting maximum speed out of our 4 physical NICs in each of our Hyper-V hosts.

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Demystifying SMB 3.x multichannel – part 7 – VM1 on Hyper-V host 1 to VM2 on Hyper-V host 2 – single NIC in each VM

From physical we are moving to virtual now – so I have created a small demo of two VMs on two separate Hyper-V hosts (connected to same switch with 4 physical NICs each). Each VM has only one Virtual Network Adapter.

As we can see we are getting 1 gigabit throughput from first to second VM. We can alo see the utilization of physical NICs on our Hyper-V hosts (transfer is using only one NIC).

Demystifying SMB 3.x multichannel – part 1 – quick introduction

I am a big fan of SMB 3.x multi-channel feature that Microsoft implemented for the first time in Windows server 2012. As I am also a big fan of Hyper-V and I want my hosts to have the ability to copy files between them (ISOs, VHDXs …) as fast as possible I wanted to create this short series of articles about multi-channel feature. I was really happy when I saw Mr. Linus Sebastian posted a video Quadruple Your Network Speed for $100 with SMB 3.0 Multichannel! so I decided to create a small series of videos to also see what advantages of using it in a production environment are and why.

For this test I used 2x Dell R730xd with 2 CPUs (Xeon E5-2620) and with Dell Intel I350 Quad-Port Gigabit Ethernet and MikroTik switch CRS226-24G-2S+.

For those not familiar with SMB 3.x multichannel I would like to point out an (old) article by Mr. Jose Barreto: https://blogs.technet.microsoft.com/josebda/2012/06/28/the-basics-of-smb-multichannel-a-feature-of-windows-server-2012-and-smb-3-0/

So in this first part I would like to show, how SMB 3.x multichannel (I am putting that x there as SMB versions are changing (table at point 4) in each release of Windows server (and client too!) works.
In this demo I will be using Windows server 2019 which uses SMB dialect 3.1.1. You can check the dialect that your servers / clients are using by typing following cmdlet in Powershell: Get-SmbConnection

smb dialect

In the following video you can see the first example – two servers connected with 4 NICs each to the switch – without any extra configuration (there are no IP addresses configured) but you can see that when we copy files from server 1 to server 2 we utilise all 4 NICs on server 1 and all 4 NICs on server 2 – it can be clearly seen also on switch. To get information how your server utilizes SMB 3.x multichannel you can use Powershell cmdlet: Get-SmbMultichannelConnection