Re: [libvirt] [PATCH 0/4] Expose FSFreeze/FSThaw within the guest as commands
On 3/3/14 17:14 , "Eric Blake" <eblake(a)redhat.com> wrote:
On 11/18/2013 09:38 AM, Tomoki Sekiyama wrote:
> Currently FSFreeze and FSThaw are supported by qemu guest agent and
>they are
> used internally in snapshot-create command with --quiesce option.
> However, when users want to utilize the native snapshot feature of
>storage
> devices (such as LVM over iSCSI, various enterprise storage systems,
>etc.),
> they need to issue fsfreeze command separately from libvirt-driven
>snapshots.
> (OpenStack cinder provides these storages' snapshot feature, but it
>cannot
> quiesce the guest filesystems automatically for now.)
>
> Although virDomainQemuGuestAgent() API could be used for this purpose,
>it
> depends too much on specific hypervisor implementation.
>
> This patchset adds virDomainFSFreeze()/virDomainFSThaw() APIs and virsh
> domfsfreeze/domfsthaw commands to enable the users to freeze and thaw
> domain's filesystems cleanly.
>
> The APIs has mountPoint and flags option currently unsupported for
>future
> extension, as virDomainFSTrim() API.
> Duplicated FSFreeze results in error caused by qemu guest agent.
Hmm, I just realized this hasn't seen any response in a couple of
months. I still haven't looked closely at the thread, but definitely
think we need to add this (or something like it).
Thanks. Based on previous discussion on last November, now I'm getting
ready to
Post "virDomainQuiesce" version, which does fsfreeze and fsthaw in a
single API,
with callback event to notify a client that guest fs are frozen so that the
client can register custom event handler to create snapshot.
It will use qemu async job mechanism to manage quiesced state and to
exclude
from the other APIs.
Please feel free to
ping the list every week or two if you don't seem to be getting a
response, rather than letting it languish for a quarter of a year!
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
Thanks,
--
Tomoki Sekiyama