I encountered the following situation when i was rebuilding my lab environment for my studies regarding SharePoint 2013, the disk active time on my data disk (holding the vm’s) would go up to 100% and the actual data write speed was dropping to 100KB/s where i was expecting around 60MB/s. This behaviour was shown for both Hyper-V and VMware Workstation when virtual machines were installed, or just idling after installation.
My configuration of this machine is as follows: an i7 processor, 32GB ram and a small SSD as a boot disk, and a larger SATA3 disk for storing the VHD’s. I know using an SSD for the VHD’s would be a better experience but time and financial constraints are what they are and since this is a lab environment a SATA3 disk should work fine for my purposes.
The image below shows the issue where active time is extremely high and throughput is extremely low:
image used from http://superuser.com/
I took the following steps to try and alleviate the issue, as my belief was first that it had to be some driver related issue i looked at installing the latest drivers.
- Install latest Windows updates to the Host.
- Install latest version of the Motherboard drivers.
- Install latest version of the Intel INF driver package.
After these changes the issue was however not resolved, and i looked at improving my experience with changing settings on the disk and hypervisor applications.
- Reformat the drive using the largest available allocation unit size.
- Create single file virtual disk files in stead of multiple smaller files.
None of these options had the desired effect of easing the drive and improving read/write performance, the VM’s were constantly freezing and the disk still showed 100% active time on the host.
What did work however was the following suggestion from Dan Sewell a user on the superuser.com website:
- Changing the Power Options settings from Balanced to High Performance.
Changing the setting, had an immediate result on the disk active time and even running multiple VM’s had no performance degradation on the disk from this point on.
You can find the link to the article and answer here: http://superuser.com/a/511481
I hope this helps you if you experience this issue.