How to enable "discard" option in Windows KVM.


Well-Known Member
Jul 6, 2016

I have a windows 10 VM that I created about 3 years ago. I have allocated it single 2TB disk and uses about 40% of it.

I can't select "Discard option" somehow.

My host system runs 4x1tb SSD in ZFS (Striped Mirrored) which allows 2TB.

My ZFS pool show over 95% usage and I would like to minimize as Windows uses only 40%.

Can somebody instruct me step by step?

Thanks in advance.Screenshot from 2019-07-28 19-54-59.png

Screenshot from 2019-07-28 19-54-44.png
I think you need virtio scsi and not virtio.

Remove the disk and re-add it with virtio-scsi, then you should be able to enable trim/discard

After you enabled discard run "disk optimisation" within windows. Then you should see free storage.
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Thanks to you after updating I can enable "discard" option.

Now that I enabled what's next step for windows 10 VM?


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