On 16/10/17 03:40, Alex Gorbachev wrote: > On Sat, Oct 14, 2017 at 12:25 PM, Oscar Segarra <[email protected]> > wrote: >> Hi, >> >> In my VDI environment I have configured the suggested ceph >> design/arquitecture: >> >> http://docs.ceph.com/docs/giant/rbd/rbd-snapshot/ >> >> Where I have a Base Image + Protected Snapshot + 100 clones (one for each >> persistent VDI). >> >> Now, I'd like to configure a backup script/mechanism to perform backups of >> each persistent VDI VM to an external (non ceph) device, like NFS or >> something similar... >> >> Then, some questions: >> >> 1.- Does anybody have been able to do this kind of backups? > > Yes, we have been using export-diff successfully (note this is off a > snapshot and not a clone) to back up and restore ceph images to > non-ceph storage. You can use merge-diff to create "synthetic fulls" > and even do some basic replication to another cluster. > > http://ceph.com/geen-categorie/incremental-snapshots-with-rbd/ > > http://docs.ceph.com/docs/master/dev/rbd-export/ > > http://cephnotes.ksperis.com/blog/2014/08/12/rbd-replication > > -- > Alex Gorbachev > Storcium > >> 2.- Is it possible to export BaseImage in qcow2 format and snapshots in >> qcow2 format as well as "linked clones" ? >> 3.- Is it possible to export the Base Image in raw format, snapshots in raw >> format as well and, when recover is required, import both images and >> "relink" them? >> 4.- What is the suggested solution for this scenario? >> >> Thanks a lot everybody!
In my setup I backup individually complete raw disk images to file, because then they're easier to manually inspect and grab data off in the event of catastrophic cluster failure. I haven't personally bothered trying to preserve the layering between master/clone images in backup form; that sounds like a bunch of effort and by inspection the amount of space it'd actually save in my use case is really minimal. However I do use export-diff in order to make backups efficient - a rolling snapshot on each RBD is used to export the day's diff out of the cluster and then the ceph_apply_diff utility from https://gp2x.org/ceph/ is used to apply that diff to the raw image file (though I did patch it to work with streaming input and eliminate the necessity for a temporary file containing the diff). There are a handful of very large RBDs in my cluster for which exporting the full disk image takes a prohibitively long time, which made leveraging diffs necessary. For a while, I was instead just exporting diffs and using merge-diff to munge them together into big super-diffs, and the restoration procedure would be to apply the merged diff to a freshly made image in the cluster. This worked, but it is a more fiddly recovery process; importing complete disk images is easier. I don't think it's possible to create two images in the cluster and then link them into a layering relationship; you'd have to import the base image, clone it, and them import a diff onto that clone if you wanted to recreate the original layering. Rich
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