> > In this case the commands look a little confusing to me, as from their > > names I would rather think they enable/disable mirror for existent > > images too. Also, I don't see a command to check what current > > behaviour is. And, I suppose it would be useful if we could configure > > other default features for a pool (exclusive-lock, object-map, ...) > > Also, I am not sure we should specify <pool-name> this way, as it is > > not consistent with other rbd commands. By default rbd operates on > > 'rbd' pool, which can be changed by --pool option. So what do you > > think if we have something similar to 'rbd feature' commands? > > > > rbd [--pool <pool>] default-feature enable <feature> > > rbd [--pool <pool>] default-feature disable <feature> > > rbd [--pool <pool>] default-feature show [<feature>] > > > > (If <feature> is not specified in the last command, all features are > > shown). > > I haven't read the discussion in full, so feel free to ignore, but I'd > much rather have rbd create create images with the same set of features > enabled no matter which pool it's pointed to. > > I'm not clear on what exactly a pool policy is. If it's just a set of > feature bits to enable at create time, I don't think it's worth > introducing at all. If it's a set feature bits + a set of mirroring > related options, I think it should just be a set of those options. > Then, rbd create --enable-mirroring could be a way to create an image > with mirroring enabled. > > My point is a plain old "rbd create foo" shouldn't depend an any new > pool-level metadata. It's not that hard to remember which features you > want for which pools and rbd create shortcuts like --enable-object-map > and --enable-mirroring would hide feature bit dependencies and save > typing. --enable-mirroring would also serve as a ticket to go look at > new metadata and pull out any mirroring related defaults. > While I agree that I don't necessarily want to go down the road of specifying per-pool default features, I think there is a definite use-case need to be able to enable mirroring on a per-pool basis by default. Without such an ability, taking OpenStack for example, it would require changes to Glance, Cinder, and Nova in order to support DR configurations -- or you could get it automatically with a little pre-configuration. -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
