[Qemu-devel] [Bug 1523246] Re: Virtio-blk does not support TRIM

[Mike Mol]

> Virtio will never support discard requests.

Why? If you don't want to write a treatise on the subject, perhaps point
at an LWN article or LKML thread where that conclusion was discussed or
reached.

> So, please rename bug to "Feature request: Refuse to operate if virtio
+ discard is requested"

Uh, if the feature as requested will never be satisfied, WONTFIX it and
create a feature that could be satisfied.  Or WONTFIX it and take no
further action. Either way, the status of things would be much clearer
to use poor schmucks who land here googling the issue.

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1523246

Title:
  Virtio-blk does not support TRIM

Status in QEMU:
  Confirmed

Bug description:
  When model=virtio is used, TRIM is not supported.

  # mount -o discard /dev/vda4 /mnt
  # mount | tail -1
  /dev/vda4 on /mnt type fuseblk 
(rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other,blksize=4096)
  # fstrim /mnt/
  fstrim: /mnt/: the discard operation is not supported

  Booting without model=virtio allows using TRIM (in Windows as well).

  Full QEMU line:

  qemu-system-x86_64 -enable-kvm -cpu host -bios
  /usr/share/ovmf/ovmf_x64.bin -smp 2 -m 7G -vga qxl -usbdevice tablet
  -net nic,model=virtio -net user -drive discard=unmap,detect-
  zeroes=unmap,cache=none,file=vms/win10.hd.img.vmdk,format=vmdk,if=virtio

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1523246/+subscriptions