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I have a Windows Server 2008 64 bit SP 2 machine on which it appears that that network I.O is very slow. I also have SQL Server 2008 R2 on the machine.

If I backup directly from server (A) to the hard drive it takes about 1m.

If I back it up from (A) to server (C), it takes 12 hours.

I have an another server(B) which backs up to (A) which takes 6 hours

Server (B) backs up to (C) takes 6 minutes.

It appears to me that anything going to and from server (A) is very slow. It has a very fast 2Gbit network card similar to the other servers. TraceRt does not appear to show any firewalls in place between (A) and (B). The network tab in Task Managers does not show any real load and time of day does not appear to matter either. Pings between all of the servers with large packets are all sub second. Neither are any exceptions appearing in the Event Log.

Trace RT without server names or IP addresses from A to C. (Not sure how useful this is.)
1 <1 ms <1 ms <1 ms
2 <1 ms <1 ms <1 ms
3 1 ms 1 ms <1 ms
4 <1 ms <1 ms <1 ms
5 <1 ms <1 ms <1 ms
Trace complete.

Added: The network load in task manager(A) is very spikey and low, different from the load on other server(B) which is more constant.

Can anyone give me any pointers about what to look at next?

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2Gbit network card? – Zoredache Nov 18 '11 at 2:31
Its actually a HP Quad Port Gigabit adapter but 2Gbps show up in Task Manager. Am I reading that wrong? – GordyII Nov 18 '11 at 3:03
Are these hosted servers? Does everything plug into the same switch? What are the geographic relationships between the servers. Can you post the tracert from A to C? – Top__Hat Nov 18 '11 at 3:51
(A) and (B) are in the same server room in the same rack on the same switch. (C) is a PC in my local office which we are holding temporary backups on until this is sorted out. All servers are located on the same campus. – GordyII Nov 18 '11 at 4:06

I would say that this is definitely a network issue of some sort. What kind of network switch do you have Servers A and B on? Is it a managed or unmanaged switch? Is it 100Mb or Gigabit?

I would start by looking at the switch. Since Server B is working correctly and it is on the same switch, we're possibly looking at a port configuration issue of some sort on the switch or a network card configuration issue on the server. If this is the case, something will usually show up in the switch logs.

One thing to look for on the switch is collisions and late-collisions on the port that server A is plugged into. If you're seeing these, you probably have a duplex mismatch. This Wikipedia entry explains what Duplex Mismatch is and why it might happen.

The switch port might also be set to a different speed or duplex depending on what was in that slot before. Verify that it is set to auto when looking at your configs.

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Have you checked your network adapter settings on Server A? Using Full Duplex may help.

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