aim60 Posted July 21, 2021 Share Posted July 21, 2021 (edited) I ran across an article whose author claimed that on recent versions of qemu, discard=unmap was functional on virtio disks. So I did some testing. I have not run all permutations, but have tested: Unraid 6.9.2 UEFI and Seabios VMs Q35-5.1 and i440fx-5.1 VMs Windows 10 and Windows 11 with the latest virtio drivers, virtio-win-0.1.196.iso Ubuntu 21.4 raw and qcow2 vdisks vdisks on XFS and BTRFS disks vdisks with and without the copy-on-write attribute set In all cases, the virtio disk was functionally equivalent to a virtio-scsi disk. On file deletion, windows unmapped blocks immediately. Linux unmapped blocks after running fstrim. https://chrisirwin.ca/posts/discard-with-kvm-2020 Edited July 21, 2021 by aim60 5 Quote Link to comment
WillCroPoint Posted October 28, 2021 Share Posted October 28, 2021 Thank you so much. Quote Link to comment
bobbowitch Posted November 29, 2021 Share Posted November 29, 2021 Thank you for this nugget! Quote Link to comment
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