Server 2008R2 Network file transfers start fast then slow way down

Grimham

Grimham

[H]ard|Gawd
Joined
Jul 20, 2004
Messages
1,613
Guys I've been looking to a solution for this and it's driving me nuts. I have Server 2008 r2 standard. When I copy or move a large file (say 400mb and up) to the the server it starts out fast and slows to a crawl. For example it will start at roughly 100MB and stay there until maybe 2/3 to 3/4 of the way through and then it's like it just hits a wall and starts incrementally slowing down. It may end at below 10MB transfer rate. I've been searching high and low and there seems to be a pretty common issue of Server 08 having network issues with large files.. I've tired every fix I could find but nothing has helped - i.e. changing tcpip offload, dma, autotunneling, enabling/disabling Remote Differential Compression,etc. I am using both Win7 and XP to transfer from/to. It happens exactly the same transferring/copying from either machine. I do NOT have this issue transferring between just the XP and Win7 computers. All drivers are up to date (I've tired different versions) and all applicable operating system updates are installed. By the way, this is a 1GB network with a completely fresh load of 2008R2, no antivirus, no installed applications.
 
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2008 r2 will load the file into memory while its transferring. That is why you will see a 1GB file begin to transfer at say 300MB/sec, but then slow way down.

If you have task manager open while you initiate the transfer you will notice your memory usage skyrocket while the file begins to copy. This is because 2008 r2 is loading as much of the file into ram as it can during the transfer to make the file transfer process more reliable.
 
Thanks for the reply, and I'm sure you are correct, and that's why my initial transfer rate can sometimes go up to 125MB a second. But I'm still trying to find out why it slows down so much. It should never drop below 50MB a second. No other machine on the network does anyway. <10MB a second is WAY too low, there is something wrong. I'm certain it's a Server 2008 issue, but I haven't been able to put my finger on it yet. Like I said, it will be moving along for about a minute at >75MB and then just nosedive and end up under 10MB - very annoying.
 
***Update***
It turns out I was not thorough enough in my testing and I forgot to try something. I had been moving/copying to a mirrored drive (two 2TB ) and the slowdown only occurs there. If I move/copy a file to my "C" drive it stays a +75MB. I guess I'm off to track down new RAID drivers and/or a utility.

***Update 2***
Found newer drivers, installed, rebooted, tested - transferring a 4gig file never drops below 80MB/s now. I'm a happy camper. Sometimes I'm so stupid though, should have thought of this in the first place.
 
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Yah RAID Parity will to that to ya sometimes. Glad it was a simple driver fix :)
 
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