To start we need to determine the raw max throughput of the network layer:
- run Iperf on source and destination servers. Source URL: http://sourceforge.net/projects/iperf/
This will be the baseline speed
- if this is really low for the network type (Wireless, 10\100, Gigabit, FC, etc) then network is the root cause.
Use http://www.ibeast.com/content/tools/band-calc.asp to convert output to something understandable.
Next we need a real world test:
- Do file copy of a large file using windows explorer from source and destination servers.
- If real world performance is far off baseline speed we need to rule the OS and filesystem out:
Start with the filesystem:
- Run CrystalDiskMark on both servers. Source URL: http://crystalmark.info/software/index-e.html
- If this exceeds the real world performance then the OS is the bottleneck
- if this matches real world performance - then the filesystem is the cause of the slowness.
Next step is to focus efforts on the worst performing of the 3 and things should improve.