With the latest requirements for snap upgrade specifying that zones must be on ZFS file systems, it occurs to me that I haven't seen anything indicating that people shouldn't be too attached to the file system they are running on. For instance, I could envision an architecture where several machines were using VCS with Cluster Volume Manager and VxFS to form a (parallel) cluster file system that holds zone roots. The same could happen with QFS. The transition to ZFS would seem to force a re-architecture.
I see mention of zone roots not being allowed on cluster file systems in the Solaris Cluster documentation, but I see no mention of it in the Zones documentation (System Administration Guide: Solaris Containers-Resource Management and Solaris Zones). This gives the impression it is a limitation of Solaris Cluster, not the Solaris Roadmap. This seems to be an important omission that needs to be addressed if, in fact, the installer is going to break what appears to be a quite workable architecture of today. One workaround for this would seem to be to create disk images (mkfile ...) on the cluster file system then create a per-zone zpool using those disk images. This would allow a cluster-wide pool of storage to be used with smallish chunks of it (disk images) being used by the various cluster nodes at different times. Of course, while this looks like it may work, it needs to be taken in context with the following paragraph. I expect that someone will pipe in saying that zones on VxFS or QFS will not support upgrade today. This, however, doesn't seem to be well publicized. Further such a statement can be taken as "it is OK to put zones on these file systems but you will not be able to use the upgrade feature." For customers that don't do upgrades anyway, this does not seem to be a limitation to consider. So... what does the new installation framework have in store for non-trivial configurations of zones that may need to be portable across machines? [In interest of avoiding the headaches with cross-posting, I have initially targeted only caiman-discuss with this message. If useful conversation that is highly appropriate for zones-discuss happens I'll post a pointer to this conversation on zones-discuss.] -- Mike Gerdts http://mgerdts.blogspot.com/
