Slow network share transfer speeds to and from server 2008 r2
I recently upgraded the hard drives in one of my servers to improve speeds. I can transfer on the local server machine a file from one hard drive to another at about 400 MB/s. The entire LAN is gigabit so I know I should be getting about 100-120 MB/s from one machine to another. I am only getting speeds of about 30-40 MB/s when I transfer to and from the windows server from or to another windows client machine, but when I transfer from one client machine to another client machine on the gigabit lan, I get speeds of about 100-120 MB/s. So I know that the problem lies within the windows server and I need to know why I I get slow speeds (30-40MB/s) when I get fast speeds locally on the server and between two other windows machines. I have checked and troubleshooted the entire network between the server and the client machines including cat5e and all in between switches and still no luck. That is why I believe it is the server having the issues. Just for a little more detail. When I transferred a large file from the server to windows 7, I went to task manager to see what percent of the ethernet port it was using. The percent was right at 30 percent. I did another test where I transferred the same file to two separate windows 7 machines at the same time. When I did that the network usage percentage on the server went to about 50 percent instead of just staying at 30%. I have been looking for 6 hours straight trying to fix the speeds by searching on google, but no luck. If you think you know what could be wrong, please let me know. Thanks!
December 21st, 2010 7:12pm

are the clients and the server on the same subnet? If not, have you looked at the router that seperates them? Tried transfering between the server and another machine on the same subnet? What is the network usage on the NIC of the server when transfering files back and forth to clients?Chris Morgan
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December 21st, 2010 8:24pm

Yes the clients are on the same subnet. All machines on the network are on the same subnet. When I did a test and transferred a large file from one windows 7 machine to another windows 7 machine, I got speeds of about 100MB/s which is the max the hard drive can transfer. When I transfer from one client to another, the NIC adapter uses about 80-90 percent at 1 gbps. I am trying to get the same speeds when transferring to and from the server that I get when transferring between two client machines. Thanks for your help and reply. Note: I just installed SP1 RC on the server to see if that would fix the slow speeds, but had no success.
December 21st, 2010 11:20pm

i would try to do 2 things a) use xcopy switch to copy b) turn off the tcp chimney on 2k8 r2 and test the speed.
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December 22nd, 2010 2:24am

Slow copy can be caused by several reasons. Here you could try: 1. Turn off Auto-Tuning. The new TCP Auto Tuning feature is included in Windows Vista and Windows 7, it uses a scaling factor communication between the server and client to negotiate a bigger window size during connection of the tow peers which might cause large file slow copy over network. Thus please press Ctrl+Shift+Enter to open the Command Prompt on Windows 7 computer, choose run as administrator. Type in: netsh int tcp set global autotuninglevel=disabled 2. Add the registry value of DisableBandwidthThrottling to 1. HKLM\system\CurrentControlSet\Services\lanmanworkstation\parameters\(REG_DWORD) This setting is available starting with Windows Server 2008 SP2. By default, the SMB redirector throttles throughput across high-latency network connections in some cases to avoid network-related timeouts. Setting this registry value to 1 disables this throttling, enabling higher file transfer throughput over high-latency network connections. The default is 0. 3. Turn off Offload. Please refer to the following blog: Slow Network copy and connection drops in Windows 7 More reference: The effect of TCP Chimney offload on viewing network traffic Very slow File copy from server to clients Best Regards DalePlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.
December 22nd, 2010 4:02am

I really appreciate your replies from the both of you. I tried all of the things both of you suggested me to try, but had no success. If you have any more ideas for me try to, please do post them all. I just think it is a little strange that I get really good speeds between two windows 7 machines, but when transferring between a server 2008 r2 and a 7 machine, I get slow speeds. I'm not sure if this could be any part of my problem, I forgot to say that I have the "File Services" role installed. Do you think that could be part of the reason for the slow speeds? Thanks again Sainath and Dale for the help and replies from you both.
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December 22nd, 2010 10:55pm

Hi , can you perform some of the tests . a) test the speed between 2k8 and another 2k8 machine b) toggle the NIC speed between full duplex to half duplex and test the speed c) test with safe mode with networking ( i want to eliminate the 3rd party applications ) d) is this specific to particular windows 2008 server or all the servers ? please test with xcopy and post the results.
December 23rd, 2010 3:08am

a) I currently only have 1 server 2008 r2 machine, so I tested between my server 2008 r2 machine that is having the problem and a server 2003 r2 machine. I ended up getting the same results. b) Made no difference so I just switched back to auto. c) No difference with safe mode. d) I only have 2 servers online right now,2003r2 is working fine, it's the 2008r2 that is being a pain. I did a few test transfers with xcopy in cmd and the speeds were the same. Note: Like I said earlier, I can use about 30% of the NIC on 1 transfer, that is what is shows as the network usage percent on both the server and client in task manager. I also noticed that when I start a separate transfer from the same server on a different windows 7 machine, the percent usage on the server doubles but the usage percent stays around 30% on both clients.
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December 23rd, 2010 5:28am

Hi , " I only have 2 servers online right now,2003r2 is working fine, it's the 2008r2 that is being a pain.", both versions are entirely different, the code base is different, with specific to SMB , w2k8 R2 uses SMB 2.0 and 2k3 uses SMB 1.0 can you post the versions of following drivers ? mrxsmb20.sys mrxsmb.sys rdbss.sys srv.sys
December 23rd, 2010 8:54pm

mrxsmb20.sys = 6.1.7601.17105 mrxsmb.sys = 6.1.7601.17105 rdbss.sys = 6.1.7601.17105 srv.sys = 6.1.7601.17105
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December 23rd, 2010 11:01pm

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