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

[Paolo Bonzini <pbonzini@redhat.com>]

Il 04/06/2013 03:02, Dusty Mabe ha scritto:
> On Mon, Jun 3, 2013 at 5:39 PM, Dusty Mabe <dustymabe@gmail.com> 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

Please attach the QEMU command line too.  I'll try to reproduce.

Paolo