A really great and powerfull new feature within Hyper-V 2012 R2 is “Bandwith Management”. With this new feature, you’re able to limit the bandwith of a particular VM. So for example, if you have a VM that generates a lot of network traffic, you can limit the bandwith. To show how powerfull this feature is, I’ve builded a small demo environment.
I’ve created two VM’s. They’re connected through the same Virtual Switich “Internal – LAN”. To generate some network traffic, you’ve have also need some data. To create some testfiles or dummy files, you can use the tool FSUTIL.exe. This tool is default available in Windows 2003 and later. In my testlab I’ve created some testfiles. The size of an dummy file is calculated in bits, so to create a file of 1 GB or 5 GB looks like:
1024 * 1024 * 1024 * 1 or 5 (or another size in GB). So first you’ll get the Bits, then Bytes, then Mega Bytes, then Giga Bytes.
1 GB = 1073741824
5 GB = 5368709120
C:\Windows\System32\fsutil file createnew D:\dummy_1GB.file 1073741824
C:\Windows\System32\fsutil file createnew D:\dummy_5GB.file 5368709120
Just copy the “dummy” files from VM1 to VM2 and let’s see how many throughput we have without some limitations. After that, I’ve enabled bandwith management and limit the VM one 15 MBps, that’s not that much 🙂 Let’s copy the “dummy” files again….now you see that the network traffic stocks at 15 MBps. That’s gonna take some time to copy all that data 😉
In this example you’ve seen how powerfull the new bandwith management feature is within Hyper-V. Whitout bandwith management, there’re no limitations at all. With bandwith management enabled, you can just give that much bandwith to a particular VM you want. That’s really great and really powerfull!!