Server is affected when it does not involves

[warrenDar]

Hello folks, we have a situation that needs inputs for Windows network admins.

Server A - PROD SQL2005 SP3 on Win2003
Server B - TEST SQL2005 SP3 on Win2003
NetAppliance - a simple and dumb net appliance storage unit that holds SQL backup files from Server A

All 3 units shared the same 10/100MB switch and all used 2000/FULL duplex.

Situation: trying to restore a 16GB SQL BAK file toServer B from NetAppliance. During the restore, the Server A's NIC thru-put traffic jumped from 50K/s to 76MB/s and clients in Server A notice response time dropped during the restore. The SQL restore uses an UNC command (\\NetAppliance\C$) to pull files.
Notice: when we copied the 16GB file raw using Windows copy, it when very fast and doesn't affect performance noticebaly.

Curious question: can anyone take stab at it as to why is it Server A is affected when it does not involves in the restore process other than sharing a switch?

 

[North323]

what are the NIC settings on the server?

 

[warrenDar]

Name [00000001] HP NC7782 Gigabit Server Adapter
Adapter Type Ethernet 802.3
Product Type HP NC7782 Gigabit Server Adapter
PNP Device ID PCI\VEN_14E4&DEV_1648&SUBSYS_00D00E11&REV_10\4&82820FC&0&1038
Last Reset 8/9/2009 5:19 AM
Index 1
Service Name q57amd64

Here's an image. I think that is what you are looking for.

 

[North323]

You probably have packet loss on the network, wich thends to get worse quickly as more date is send trough the line. This would explain why the file transfer seem to be unaffected, as it's reasonable light-weight traffic compared to UNC.

- Open a ping from the machine accessing the UNC to the machine it is accessing it from. See if there are any problems. Now with the ping still open ( use -t on windows to keep it from quitting after 3 runs) start transfering data and see if if that has any effect on it.

- Errors caused by network connectivity can cause this. Mismatched MTU sizes or truncation of a packet at a router can result in this error when files larger than the largest packet size are copied over the network. In essence, the network connection is the media that has the physical problem.