Windows Host Windows Guest Degrading/Slowing Network Speeds

[LeonardRogan]

Hi All,

I have a HP DL380Gen8v Performance server with 15k SAS drives and Windows Server 2012 R2 as the Host OS. 4 inbuilt GigaBit network Adapters.

I have three of these servers.

They were put in place to virutalise the previous servers with the methods to get the virutal environment as part of the StorageCraft solution.
That is, from a StorageCraft shadow protect backup the virtual environment was built with VirtualBox.

On this particular server I have two Guest OS/s. Both are Windows Server 2008 R2.

Both Servers have Bridged network adapters connecting to the real network. Both were confrigured using Intel PRO MT Server Adapter.

Both guests have been running for the same time which is around 9 months now.

One of them is having a real issue with the speed of the network now and it's slowly getting worse.

The throughput used to be around 40mbps which we can deal with as being acceptable. Now it's around 4mpbs which is not acceptable. This is having a real impact on the overall performance and the nightly backups not finishing in time for trade.

I have searched far and wide for an answer and I'm struggling to find something that has worked.

On the other guest server (not having the issue) I installed the paravirtualized adapter which was an effort in iteslf and it went from 40mbps down to 10mbps, so I changed it back.

How can I speed up the network on the 2008 R2 Guest from about 4mbps up to where it should be?

VirtualBox Version is:
4.2.4r81684

Host Server Windows Server 2012 R2 with 4 x Intel GigaBit Adapters.
Guest OS 2008 R2 with Intel PRO 1000 MT Bridged adapter.

Any assistance would be greatly appreaciated.

Cheers
Leonard