SBS 2011 - extremely slow network performance

Data transfer on the server from logical Drive D to D is about 65 MB/s, D to C about 50 MB/s

Data transfer on Windows 7 machine from Server to Windows 7 machine - 11 MB/s

Based on this article:  

I tried:

netsh int tcp set global rss=disabled
netsh int ip set global taskoffload=disabled
netsh int tcp set global congestion=none


No change

Change parameters back:

netsh int tcp set global rss=enabled
netsh int ip set global taskoffload=enabled
netsh int tcp set global congestion=ctcp


The connection actually seems slower.  Initial connection to mapped network drive takes about 20 seconds then when trying to transfer the file (either disabled or enabled) it still runs at ~11 MB/s

How can I fix this problem?  I did NOT have this problem with Server 2003.

Adam DIT Solutions DeveloperAsked:
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Larry Struckmeyer MVPCommented:
Usual advice is to disable SMB signing.  But you might also have a failing nic, a failing switch or port(s) in the switch, or a bad patch cord.  Since the symptom is evidenced from more than one system probably not in the wall wiring or rfi interference unless your company has installed some new powerful alien listening jamming device.
Adam DIT Solutions DeveloperAuthor Commented:
Well...we were trying out our new invisible dish because we know the inevitable is coming and wanted to be prepared, but after we fried a few employees with microwave bursts (they always forget to turn the thing off) we decided to put it on a separate building! :)

"They" say SMB signing is only a 10% hit on performance.  While every drip counts, I don't think that is the main culprit.

Network switch, ports, patch cords - all good (tested with tester) and communication is only problematic with this SBS 2011 machine.  Another Windows Server 2008 R2 on the same switch - no problem.

Try again? :)
Larry Struckmeyer MVPCommented:
Do you have a reference for the 10%?

You could try it on one system to test.  It is just a reg entry  11 Mbs sounds strangely like wireless...

What type of drives and in what type of RAID?  What controller?   Drives not full/filling/fragmented?  

btw, do you mean MBs?  The usual notation is mbs, so fast Ethernet is 100 mbs, at best and the actual "normal" would be 60% or about 60 mbs.   By that standard you do very well.
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Adam DIT Solutions DeveloperAuthor Commented:

Just a random site I found when looking at turning off SMB.

No, these are all wired machines, just VERY slow transfer rate.  This server has only been in place a few months and originally there was a hard drive issue with the RAID array so I had to replace the array and that fixed the internal transfer speeds back up to 60 mb/s - internal from volume to volume only.

Raid 1 - on the first 2 drives
Raid 5 - on the other 3 drives

Just 7400 RPM drives - not high-end, onboard controller.  Drives are not full, filling or fragmented.

Larry Struckmeyer MVPCommented:
Another thing that would affect this, although I can't positively say how much might be  the amount of free RAM.  SBS 2011 is very RAM dependent and should have Exchange limited per this from Third Tier:

RAID one will give slightly better read speeds than a single drive, and slower write speeds.  Raid5, with three spindles is slower than RAID1 because of the calculations it has to make to write.  But 7400 RPM SATA drives configured the way you list will be "slow".

My guess is a combination of free RAM,  SMB signing and SATA drives in the slowest possible configuration.

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Natty GregIn Theory (IT)Commented:
What Larry said, Ram play a big part, also bottle neck on the network, processor speed, mother board speed, and finally microsoft, built in buffer of file transfer always drive me nuts, however same device running linux server copying is priceless.
good news to go around microsoft set buffer, which you cannot fix I use tera copy, supperfast and microsoft fixed coping in windows 8.1 also as fast as teracopy.
11MB/s is typical speed for 100Mb network.
Since 100Mb/8b (1byte) = 12.5MB which is theoretical maximum for 100Mb network.

Check your network links between host and server. Some link is 100Mb.
If all links suppose to be 1000Mb check their real speed for each link and set speed manually.  

Adam DIT Solutions DeveloperAuthor Commented:
Still working on this problem, no resolution as of yet.  Since there are no other major issues with performance on other machines I am thinking this is more of a tweaking need on the server itself.   Any other ideas are welcome.
Check, just in case, network card is it maybe working in half duplex mode?
This can cause extreme congestion.
And what is network speed?
Adam DIT Solutions DeveloperAuthor Commented:
Problem not fully resolved yet, but Larry was very helpful.
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