Hi,
does the linux kernel provide a mechanism whereby applications can
register themselves
to be notified when a snapshot is being taken of the volume they might
be writing to.
If there is no such framework then how do backup applications
guarantee ( application level ) consistency. I have seen freeze_bdev
and friends which work for file systems and how the device mapper uses
them. But when it comes to application level consistency, a mechanism
is required to give the application a chance to flush & quiesce its
writes so that the backup taken will be consistent for the application
also. Windows has the VSS ( Volume Shadow Service ) which provides an
elaborate framework for this. Is anyone working on something similar
for Linux and if not why is it not such a worthwhile idea ?
Regards
BD
On Tue, Nov 15, 2005 at 01:15:54PM +0530, Block Device wrote:
> Hi,
>
> does the linux kernel provide a mechanism whereby applications can
> register themselves
> to be notified when a snapshot is being taken of the volume they might
> be writing to.
>
> If there is no such framework then how do backup applications
> guarantee ( application level ) consistency. I have seen freeze_bdev
call sync and mount read-only, or go down to init 1.
Coywolf
> and friends which work for file systems and how the device mapper uses
> them. But when it comes to application level consistency, a mechanism
> is required to give the application a chance to flush & quiesce its
> writes so that the backup taken will be consistent for the application
> also. Windows has the VSS ( Volume Shadow Service ) which provides an
> elaborate framework for this. Is anyone working on something similar
> for Linux and if not why is it not such a worthwhile idea ?
>
> Regards
> BD