Question Safe to Defrag a drive with dual boot OS, VM?


Apr 7, 2019

I have 1 single hard disk drive on my laptop. I divided it into 2 partitions, C and D.
Windows 10 is installed on C:/

I installed a Linux distro on D:/ which I can dual boot from (Grub shows up every time I boot windows, allowing me to select what OS to boot)

Now i googled on this topic but can frankly find any definitive answer, or that it hasn't been touched too much upon. Some tidbit I stumbled upon is that Linux in general doesn't ever need to be defragged at all unike Windows. I analyzed my C:/ and it has 11% fragmentation, while D:/ has 50% fragmentation.

I also have my virtual machine (VMWare) installed on D:/ and I frequently restore my VM to a previous state for testing out things. Maybe that is what's causing so much fragmentation.

If I defragged both drives as they are right now from Windows 10, will it have any adverse effects?
Also, what if both OS were in the same partition (let's say C:/), is defragging unadvisable?

Also in what order should I defrag.

"Remember that defragmentation from outside the virtual machine (VM) isn't the same as defragmentation inside the VM. VMware recommends that you use a disk defragmenter inside the VM first. In the case of Windows, this can be the built-in defragmentation service.

Once that defragmenter has completed its job, power down the VM and run vmware-vdiskmanager (or click Hard Disk, Utilities, Defragment inside the VMware Workstation UI). If you want the best performance, follow up with a third pass on the host itself, defragging its drive as a final step."

I would suppose its: Defrag first inside the VM then > Defrag on the host