From: Paolo Bonzini <pbonzini@redhat.com>
To: "Richard W.M. Jones" <rjones@redhat.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Trying to get fstrim / discard=unmap to work
Date: Mon, 10 Mar 2014 17:57:01 +0100 [thread overview]
Message-ID: <531DEEDD.20007@redhat.com> (raw)
In-Reply-To: <20140310161421.GB6744@redhat.com>
Il 10/03/2014 17:14, Richard W.M. Jones ha scritto:
> On Mon, Mar 10, 2014 at 04:11:20PM +0000, Richard W.M. Jones wrote:
>> Guest:
>> - guest kernel: 3.13.4-200.fc20.x86_64
>> - ext4 guest filesystem
>> - fstrim from util-linux 2.24.1
>> - cat /sys/block/sda/device/scsi_disk/*/provisioning_mode
>> unmap
>
> I noticed that I wasn't mounting the guest filesystem with '-o discard'.
> However it still doesn't work even after adding this option.
Works here:
$ qemu-system-x86_64 -drive
discard=unmap,file=$HOME/jeos-19-64.qcow2,id=ff,if=none -device
virtio-scsi-pci -device scsi-disk,drive=ff -vnc :0 --enable-kvm
Before test:
$ du -h jeos-19-64.qcow2
1,6G jeos-19-64.qcow2
After "dd if=/dev/zero of=foo bs=1M count=300":
$ du -h jeos-19-64.qcow2
1,8G jeos-19-64.qcow2
After "rm foo; fstrim -v /":
$ du -h jeos-19-64.qcow2
1,4G jeos-19-64.qcow2
I also set a breakpoint on fallocate64, and it was called.
Paolo
next prev parent reply other threads:[~2014-03-10 16:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-10 16:11 [Qemu-devel] Trying to get fstrim / discard=unmap to work Richard W.M. Jones
2014-03-10 16:14 ` Richard W.M. Jones
2014-03-10 16:57 ` Paolo Bonzini [this message]
2014-03-10 17:15 ` Richard W.M. Jones
2014-03-11 20:00 ` Richard W.M. Jones
2014-03-12 17:55 ` Paolo Bonzini
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