Slow network transfers TO (but not from) Server 2008

[agreenbhm]

I've had it up to here with this **** network transfer problem! I had Server 2003 installed on my server and all was well. Now I'm running Server 2008 x86 on the server and I can't seem to fix this issue.

Issue is this: transferring files TO my server from my workstation (was running Vista x64 until yesterday, when it is now running 7 x64, but the problem occurs on both) is very slow. The transfer starts off fast (10 to 11MB/s) but then drops to about 2.5-3.5MB/s after about 5 or 10 seconds.

I am trying to copy my Outlook PST file (800MB +/-). I copied the file to the server from the workstation (using the workstation's Explorer) and it goes slowly (like described above). I copied the file from the server to the workstation (from the workstation's Explorer) and it is fast. I copied the file from the server to the workstation (from the server's Explorer) and it is fast. I copied the file from the workstation to the server (from the server's Explorer) and it is fast.

So this only occurs using Vista/7's Windows Explorer. However, Vista was copying files at a fine speed to the server when it was running 2003. Ever since the 2008 installation I've been having the issue. So I'm fairly certain it's a 2008 problem (or at least a problem with my install).

I've tried numerous registry tweaks and NIC settings. I have two NICs in the server, and the issue occurs regardless of which one i'm using to copy the file. I've enabled TCP offloading, disabled it, changed max IRQs, changed MSCSS, changed TCP ACK, changed 2008's TCP autotuning, and countless other things.

Does anyone have any idea how I can fix this?

[DigeratiPrime]

Greets What is the service pack level of these machines? Is this a wired or wireless network and what is the link speed? Anything you think we should know about the hard drives in these machines?

[agreenbhm]

The server is running SP2 and my workstation was running Vista SP2 but is now running Win 7 RTM. The connections are wired and running at 100mb.

[jcarle]

Please run iperf found here : http://www.noc.ucf.edu/Tools/Iperf/default.htm

To determine if it's a network issue or a disk issue.

The executable is standalone, simply download and run it with no parameters on the server and then download and run it on your local machine using -c <ip> to connect to your server.

[Mr Snrub]

Are the machines in a domain, and have you looked at SMB signing?

Have you taken a look at a network trace copying the same file in both directions so see what is different?

(I would be looking at MTU negotiation, sliding windows, SMB block size 64k vs 4k, selective ACKing, delayed ACKs, that kind of thing.)

[agreenbhm]

Please run iperf found here : http://www.noc.ucf.edu/Tools/Iperf/default.htm

To determine if it's a network issue or a disk issue.

The executable is standalone, simply download and run it with no parameters on the server and then download and run it on your local machine using -c <ip> to connect to your server.

I had to disable the firewall (or make an exception for the needed port) to run this utility. Here is the result:

[148] local 192.168.0.113 port 58677 connected with 192.168.0.103 port 5001

[ ID] Interval Transfer Bandwidth

[148] 0.0-10.0 sec 109 MBytes 91.5 Mbits/sec

Seems pretty good to me. Unfortunately, with the firewall off, the problem persisted.

Are the machines in a domain, and have you looked at SMB signing?

Have you taken a look at a network trace copying the same file in both directions so see what is different?

(I would be looking at MTU negotiation, sliding windows, SMB block size 64k vs 4k, selective ACKing, delayed ACKs, that kind of thing.)

The machines are in a workgroup. I hate to say it but I don't really have a clue about any of the other things you're talking about.

I have noticed that whenever a file is copying it seems to copy in bursts. It starts fast (like I originally said), then drops, then goes for a few seconds at the slow speed, then stops, then starts, etc. Watching the network tab of Task Manager shows that network utilization drops to 0% for a few seconds, then back up to whatever it was using 50% or so.

[agreenbhm]

Ok, I just did another test of my own (I created a shared folder on the C drive, which is a standalone disk) and copied the file to it, and it went just fine. The volume I'm trying to copy to is a Windows software Raid 1. According to disk management the disks are healthy. I'm still convinced that the problem was caused by 2008 (since 2003 had the same setup without issue). Is there any way to fix this?

[Mr Snrub]

So it's sounding more like disk writes to the software RAID is slower than reads, if I follow you correctly?

The iperf test and your local disk share test would imply the network throughput is not the issue.

If you copy a huge file (or a collection of files) between the local volumes, is the C: -> RAID slow but RAID -> C: fast?

Mirrored RAID writes can be slower than single disk writes as each I/O turns into 2 and both have to report completion, whereas reads don't have that problem (either device, or the same one every time, satisfied the single I/O request).

Software RAID in particular is something I've avoided because of this kind of issue.

[eyeball]

EDIT: Sorry i got this wrong in my orginal Post, now edited:

I have seen this type of thing before, steps to replicate problem as follows:

1) Use a fairly large file (ie 15-20gb)

2) On a 2008 server UNC back to a vista /win 7 machine and copy the file to the server

3) Bring up taskmgr on vista/win7 and watch the ram usage increase until all available Ram is consumed and the transfer grinds (almost) to a halt.

Any other way round (UNC'ing from to vista/win7 to server etc) is fine but this paticular way produces this error. I have tried this with various machines and clean installs.

Has anyone else seen this and does this sound like what you are experiencing agreenbhm?

Thanks

EDIT 2:

From testing i have done in the past i can say that this also happens between 2 Vista clients but NOT between 2 server 2008 servers..

Anyone got insight into this issue?

Edited August 11, 2009 by eyeball

[Tripredacus]

I had this problem also, and the fix is documented here:

http://www.msfn.org/board/index.php?showtopic=122871

I know its in the 2003 forum... can't do much about that.

[DigeratiPrime]

Might this be a QOS issue?

[jcarle]

It is not a network issue. It's a data transfer issues between the network card and the hard drives.

[Mr Snrub]

It is not a network issue. It's a data transfer issues between the network card and the hard drives.

Yeah, unless I misunderstood the last post from the OP, he said copying over the network to write to a share on the C: drive is fine, but copying the same data to write to a share on the mirrored RAID volume is slow.

At this point I'd be looking at write performance to that RAID set by bouncing a file back and forth between the 2 local volumes.

[Tripredacus]

It is not a network issue. It's a data transfer issues between the network card and the hard drives.

Yeah, unless I misunderstood the last post from the OP, he said copying over the network to write to a share on the C: drive is fine, but copying the same data to write to a share on the mirrored RAID volume is slow.

At this point I'd be looking at write performance to that RAID set by bouncing a file back and forth between the 2 local volumes.

If that's the case, it would be helpful to know whether it was a hardware, hardware emulated or software RAID.

[jcarle]

If that's the case, it would be helpful to know whether it was a hardware, hardware emulated or software RAID.

He already told us, see below (taken from his previous post).

... The volume I'm trying to copy to is a Windows software Raid 1. ... I'm still convinced that the problem was caused by 2008 (since 2003 had the same setup without issue). ...