Windows Server 2008 R2 software Raid-5 slow over network

networkingraid5software-raidwindows-server-2008-r2

I'm using Windows Server 2008 R2 for my file server. I put a 7x1TB software raid-5 on it, and let it resynch. OS is installed on a separate disk.

Now I'm getting very poor write speeds to the raid volume over network.

  • If I copy files to the Raid volume over the network, write speed is poor (~5MB/s).
  • If I copy files to the OS disk over the network, write speed is good (~70MB/s).
  • If I copy files from the OS disk to the raid volume (no network, directly on the server), write speeds are good (~80MB/s).

Network is a 1000 Mb/s home network, using Cat 5e cables. I've used standard Windows SMB for the file transfer. Speeds are measured using TeraCopy. Server doesn't have any 3rd party software installed to it. Assigned Roles are File Services (not really configured though) and Print and Document Services (same thing).

Any idea why the write speed over network to the software Raid-5 volume is so slow?

Edit for additional info: Read speeds are fine from the raid volume over the network (~55MB/s). When writing over the network, cpu usage is below 5%. Server is a Intel C2D E4500 with 4GB of RAM.

Best Answer

The problem was with latest version (2.1) of TeraCopy (a replacement for standard Windows copy program). It seems that it cannot handle networked raid-arrays very well. Uninstalling it did the trick.