Thanks Jason, I think I'm going to start with a bash script which SSH's into the machine to check if the process has finished writing and then calls the fsfreeze as I've got time constraints to getting this working. But I will definitely revisit this and see if there is something I can create which will do as you have described, as it would be a much neater solution.
Nick > -----Original Message----- > From: ceph-users [mailto:[email protected]] On Behalf Of > Jason Dillaman > Sent: 08 July 2016 04:02 > To: [email protected] > Cc: ceph-users <[email protected]> > Subject: Re: [ceph-users] RBD Watch Notify for snapshots > > librbd pseudo-automatically handles this by flushing the cache to the > snapshot when a new snapshot is created, but I don't think krbd > does the same. If it doesn't, it would probably be a nice addition to the > block driver to support the general case. > > Baring that (or if you want to involve something like fsfreeze), I think the > answer depends on how much you are willing to write some > custom C/C++ code (I don't think the rados python library exposes > watch/notify APIs). A daemon could register a watch on a custom > per-host/image/etc object which would sync the disk when a notification is > received. Prior to creating a snapshot, you would need to > send a notification to this object to alert the daemon to sync/fsfreeze/etc. > > On Thu, Jul 7, 2016 at 12:33 PM, Nick Fisk <mailto:[email protected]> wrote: > Hi All, > > I have a RBD mounted to a machine via the kernel client and I wish to be able > to take a snapshot and mount it to another machine > where it can be backed up. > > The big issue is that I need to make sure that the process writing on the > source machine is finished and the FS is sync'd before > taking the snapshot. > > My question. Is there something I can do with Watch/Notify to trigger this > checking/sync process on the source machine before the > snapshot is actually taken? > > Thanks, > Nick > > _______________________________________________ > ceph-users mailing list > mailto:[email protected] > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > -- > Jason _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
