Slow Internet access on Windows 2003 Virtual Server
Posted on 2012-08-21
We have a Hyper-V server on which the Internet response times on a virtual Terminal Server are extremely slow. At another office we have two physical Terminal Servers on dedicated servers and the Internet response is much better (albeit any pages using Flash cause issues and Firefox is much slower than IE).
I have read a number of articles about not using certain offload features of server NICs on a Hyper-V server. The articles imply that these settings are helpful on non-Hyper-V servers, but not when the server runs Hyper-V.
I would appreciate advise on how the NICs on our server should be set.
The Hyper-V server runs Win 2008 R2 Enterprise on a HP ML350 2 x Xeon E5504 @ 2GHz with 30GB RAM, 2 x HP NC326i Dual Port Gigabit server adaptors, 2 x 2-port SAS 146GB drives as a RAID1 array and 4 x 2-port SAS 300GB drives as a RAID1+0 array.
The Hyper-V machine was set up by the installers to run DNS, File and Print Services, Hyper-V and Symantec Backup Exec runs on this machine.
Virtual machine 1 is Domain Controller/application/file and print server/Symantec Endpoint server, with 8GB RAM, Windows 2003 Enterprise, 1 Virtual processor, 80GB system drive,
100GB Data drive.
Virtual machine 2 is a Terminal Server, with 12GB RAM, Windows 2003 Enterprise, 1 Virtual processor and 80GB system drive.
On both of the Hyper-V machine NICs, the following settings apply:
IPv4 Checksum Offload - Rx & Tx Enabled
Jumbo Packet - Disabled
Large Send Offload Version 1 (IPv4) - Enabled
TCP Checksum Offload (IPv4) - Rx & Tx Enabled
UDP Checksum Offload (IPv4) - Rx & Tx Enabled
and these are reflected on the Virtual machines.
No more than 10 users are on the Terminal Server at any one time, using applications installed on the DC. There are also 7 users who use applications on the DC from PCs connected to the LAN.
The LAN goes through a HP gigabit managed switch, servers run at 1Gbit, Thin Clients/PCs run at 100Mbits.
Connection to the Internet is via a Unix firewall with a 100Mbit LAN connection and an ADSL Annex M broadband connection with 1.4Mbits download/1.2Mbits upload.
Internet response from PCs on the LAN is fast, so the problem clearly points to the virtual server environment.