Extremelly slow LAN speed on Server 2008 and SBS 2008

Andrej Pirman
Andrej Pirman used Ask the Experts™

I have already escalated this case for few times, but without sucess.

My problem are 2 Windows 2008 servers, 1 Server 2008 STANDARD and 1 SBS 2008.
All except the following is OK:

1st server is 2008 Standard, and is on physical machine, QuadCore XEON, 8 GB RAM, RAID 10 SAS disks, ALL Gigabit NIC's and Gigabit Switches.
100 Mbps optical fibre internet, which runs almost full 100 Mbps in BOTH DIRECTIONS.
MY clients on Gigabit LAN have all interconnection transfer speed between themselves up to 500 or 600 Mbps, except with this SERVER 2008 - only 0.5 - 1 Mbps download speed (from SERVER to CLIENT) max!!!

2nd server is SBS 2008, running on VMware ESXi on same HW as above.
There are 2 virtual machines, one Windows 2003 and one Windows 2008.
Again, problematic is UPLOAD speed from ANY CLIENT to this SBS 2008 - only 2-3 Mbps on Gigabit network.
All other speeds in ANY direction are Gigabit-like.
Also, transfer speeds TO and FROM other virtual machine (win 2003) on same HW are also Gigabit-like

I have tried almost anything on both machines:
- reinstalled NIC drivers
- patched to latest updates
- changed cables
- TEAMED 2 NIC's into team
- played with "autotuninglevel" parameters

But nothing helped!
The common pitfail is: ONLY Win 2008 technology is problematic. And only transfer speed in one direction and one destination is problrmatic (for example - on 1st machine, internet speed is 100 Mbps, but LAN speed is below 1 Mbps).

Here is my paralel post, but there is no usefull advice: http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/Windows_Server_2008/Q_24273725.html

It is NOT that I want to fine-tune. My current LAN speeds are practically useless, so I need to solve those problems asap.

Suggestions welcome.
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I suggest that you check your speed and duplex level in the ESXi Server. Set the speed and duplex to manual instead of Auto-Negotiate and update the thread.
Also when the SBS 2008 VM was created what did you choose for the vNIC Option. Did you choose the enhanced-vmxnet option or the flexible option ?
Please update whether you have installed VMware Tools inside the SBS 2008 VM.
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Top Expert 2012
Disable TCP Checksum, IP Checksum, TCP Offload or IP Offload. These will cause network slowness. What AV are you running in the VMs. Some AVs like Symantec Endpoint causes network issues in 2008.
Chris GralikeSpecialist
If you have managed switches, see if there are exessive broadcasts, duplex mismatch, or other problems on the ports connected to the machine. If switch supports it, enable debugging on the specific ports.


Wow, guyz, thank you for bunch of advices.
All those are production servers, so I'll try suggested changes only today during the night. I'll report back with results.

Regarding VMware:
- NO, unfortunatelly VMware Tools do not want to get installed on this specific virtual machine 2008
- YES, speed of both NIC on ESX is set to 1 Gbps full-duplex manually
- VM's NIC is Intel PRO 1000 NT and if I look at driver's properties, there is nothing related to virtual*, enhanced-vmxnet option or the flexible option
hmmm....might it be that machine was converted from PHYSICAL to VIRTUAL, and that's where troubles came from?
Top Expert 2012

What AV are you running?


AV is NOD32, version 3.x on both systems.
But I think it should not interfere, since it is just simple AV for occasionall file scanning, without Firewall and with disabled real-time scan.
Top Expert 2012

There have been problems with NOD, SEP, and a couple more AV softwares that have been causing this issue on Server 2008. What I have found is that McAfee and AVG works well on this edition of server without slowing the network down and hanging network services. I would remove NOD for testing.


I uninstalled NOD 32 from SERVER 2008 machine, but there is no change. Still extremelly slow!
I also uninstalled Network adapter from server, and reinstalled it, disabled it and enabled again...but again, no change.

Here are latest results in pictures, showing transfer of 150 MB file from XP CLIENT --> SERVER:
- on 1st picture SERVER is 2008
- on 2nd picture SERVER is 2003
Both servers are virtual machines on same ESX host, connected with Gigabit Full-Duplex (manually set) same NIC to same network, and in same AD Domain. And at time of testing, none of servers had NOD32 installed.
So everything is the same, except OS.

I'm becoming slightly mad...


Digging into problem this night, I found some specific and interesting things:

- in problematic SERVER 2008 (inside ESX host) the default NIC adapter was Intel 1000E, and virtual machine was using  E1000 driver. I tried to install VMware Tools, but all I've got was a series of BSOD with "tcpip.sys" as faulty driver.

- so I simply added new NIC to this VM, of type "flexible" and installed it with AMD drivers. Then I disabled existing Intel E1000 adapter and moved all services to the new AMD Network Adapter.
Many things got broken in this step, beginning from Networking, and then seizing down many things way down to Group Policy, since SYSVOL share was not available anymore. So I spent few hours repairing domain controller, but finally I get it to work. After doing repairs, server was hooked at logon screen "Applying computer settings..." for more than an hour, but he was busy and did his job perfectly.

And not to mention main HEUREKA - Network speed is faster than light in both directions :))

- VMware Tools still refuse to install with "General system error occured: internal error". I tried to install it manually, but I simply cannot find WINDOWS.ISO VMware Tools installer package, actually...cannot find it on ANY of my ESXi host installations, neither on guest VMs.
So I quit from installing VMware Tools for now.

I was really sure problem was gone, but NO - approx. half an hour later, I tested file transfer speed in both directions and again exact the same symptoms as before!



Being determined to dig into problem and solve it, I spent whole night at the facility and finally I found the problem cause and solved it. It was something unbeleiveably strange - domain replication hit tombstone limit!

This SERVER 2008 is the only DC in domain, but it was initially setup by doing live migration from existing DC from Windows 2000 OS. The catch was that after migration was done, old DC was not demoted from AD structure, but it simply died of HW failure.
Domain replication hit the problems, tombstone limit was due, and FSMO roles were not properly distributed. So NTFRS was failing, GPO became corrupt, and after reboot server was not able to became DC.
I won't describe the whole chain of problems here, which all arrised after I started digging. The main point is that after I did Authoritative Restore and after I rebuilt GPO, all netwroking problems dissapeared!

Thank you all for help.
I actually found sollution myself, but will split points for good intentions :)
Chris GralikeSpecialist

Those are some serious problems. Do check/Monitor all the FSMO roles over the comming period just to make sure.

If running 2008 the command is buildin, have a look at this arti

Good luck!

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