Re: [Qemu-devel] fstrim and cache=none

[Dusty Mabe]

On Mon, Jun 3, 2013 at 5:39 PM, Dusty Mabe <address@hidden> wrote:
>
> It is possible that I was mistaken. Now when I switch back to
> cache=none I am still able to execute trim operations. I'll
> investigate a little more into my exact steps that I took and see if I
> can come up with a reproducer for the issue I observed.
>

Paolo,

I was mistaken. I had added a disk to the guest and then created an
ext4 FS on the disk. I then noticed that I couldn't perform fstrim
operations. I then examined the xml and the only difference between
this disk and the other disk in the system was the cache=none. So I
removed cache=none and then shutdown/booted the guest. After the
reboot all worked fine so I assumed it was the cache=none line. This
was wrong.

Actually it is the formatting of the filesystem. When i create an FS
in the guest it disables discard. There are also some errors printed
in /var/log/messages.

Please see the output in file at the following location:

http://dustymabe.com/content/qemu-devel-mail.txt


Looks like it could be a bug (linux bug?) but I'm not sure.

Thoughts?
Dusty