How am I getting 200-220MB/s over standard GigE between 2 computers?

westrock2000

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I have 2 computers right next to each other and each one has a dedicated GigE NIC with a crossover cable between the two. I give them dedicated IP addresses and use that for Windows mapping network drives. For some reason I get 200MB/s between these 2. I have used Jumbo Frames and stuff in the past, but normally that's only good for like 110-120MB/s.

KbOumrp.jpg
 

pendragon1

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I have 2 computers right next to each other and each one has a dedicated GigE NIC with a crossover cable between the two. I give them dedicated IP addresses and use that for Windows mapping network drives. For some reason I get 200MB/s between these 2. I have used Jumbo Frames and stuff in the past, but normally that's only good for like 110-120MB/s.
magic, be happy. ;) what nics are you using(models)?
 

westrock2000

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What does your ethernet ports show?
Well this is interesting. What's happening is that both NIC's are being utilized. The dedicated network between the 2 computers and then also the normal network NIC that the computers communicate publicly on. So I guess it's aggregating the bandwidth of both NIC's. I didn't know this was done by default. I thought this was only possible with special setups.

p98YZ5S.jpg
 

pendragon1

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did you enable nic teaming or have either cards oem software installed that might enable it?
 

bman212121

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For any program to saturate multiple links, you need to have as many or greater number of streams going as the number of links. Normally you'd be bonding together two ports via LACP to act as one, but even then you still need multiple streams to take advantage of it.

What you've stumbled upon is that SMB3.0 was designed to recognize multiple connections and use them in aggregation together. This has actually been a thing Since Windows 8 / Server 2012. I can't find the blog post anymore but I remember reading about it and testing it out back in 2012 and it worked flawlessly out of the box. It is link agnostic and I think we even proved you could augment bandwidth if you used multiple wireless links. It's pretty neat stuff that a lot of people probably don't realize is baked right into every Windows OS.


EDIT: Here you go!

https://docs.microsoft.com/en-us/ar...-a-feature-of-windows-server-2012-and-smb-3-0


Courtesy of this [H] post from 2014.

https://hardforum.com/threads/windows-server-2012-r2-and-smb-multichannel.1824605/
 
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westrock2000

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did you enable nic teaming or have either cards oem software installed that might enable it?
Nope, nothing special done. Using whatever drivers Windows installed. After realizing what was happen I look up link aggregation and saw that teaming stuff. But that looked to be something else (and not sure if even supported anymore on Windows Pro).
 

bman212121

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Nope, nothing special done. Using whatever drivers Windows installed. After realizing what was happen I look up link aggregation and saw that teaming stuff. But that looked to be something else (and not sure if even supported anymore on Windows Pro).

Correct, this has nothing to do with teaming or Link Aggregation. You would use those features to compliment this in order to provide fault tolerance to the link. SMB Multichannel is purely a software implementation so it works on any combination of hardware that provides multiple connections.
 

SamirD

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Very cool to see this in action and how little it took to make it happen. Makes me wonder how much faster a 2.5Gbe card in each system would make this setup (or 10Gbe). If the systems are physically close enough 10Gbe cards with a dac can be had for as cheap as $60 shipped.
 

bman212121

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Even now storage is still the limiting factor. If you had 2 x 2.5gbe cards you'd need to be able to handle roughly 640MBps of traffic. That's more than SATA3 offers, so you'd need MVNe SSDs to saturate it. If it were spinners that's about the amount of bandwidth I can squeeze out of a full DAS shelf with 12 3.5" HDDs. From what I've seen with 10gbe, you'd probably need to start making tweaks as it's not trivial to just saturate one link, let alone two.
 
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