Thinking in the long term and provided that the community grows, how will Rockstor handle a bigger update, either to the Linux kernel or BTRFS?
Perhaps one that changes how the base system may behave. And if we aren’t on the latest Rockstor will we have to wait for a working platform to update to.
I do not know enough about FS to make this sound plausible but what if when RAID5/6 support in BTRFS becomes proven to be stable but it requires a large version upgrade and only works for newer editions instead of updating OS?
Recently with the Ubuntu 16.04 LTS some users had trouble updating from 14.04 LTS and then the Ubuntu team released a statement saying to wait until July for 16.04.1 or some number to allow for native update capability. People from 15 were fine though.
Since this will be handling my personal data, I want to make sure there is a path Rockstor team will follow whether it is auto-updating systems in a stable way or providing support for everyone in a timely manner.
There are just lingering questions I keep having before my setup becomes ready to order and my parts get mailed so I wanted to take the time to ask the community some questions to reassure me, I guess. I hope this isn’t a stupid question.
BTRFS disk format is not expected to change as documented in the project wiki. Linux kernel in general and btrfs module in particular receives regular contributions which is why we stay on a relatively newer kernel breaking from the stock CentOS kernel. This kernel is packaged and distributed by the elrepo project. So, Rockstor is like Archlinux in terms of more frequent iterative updates to the kernel and Rockstor specific bits. Because of this iterative approach, the chance of incompatible updates is minimized.
Suppose BTRFS makes an incompatible change, which is very very unlikely and equally applies to any other filesystem, then you could backup all data to another system and restore after updating. From Rockstor point of view, we’ll try to provide tools and documentation to to help. Again, this is very unlikely. I think in case of anything close to such scenario, some btrfs migration tool would already be in place to aid in development.
A slightly more probable scenario is an incompatible update within Rockstor that’s not really btrfs related. Like if we are forced to do so due to upstream/centos update. In such case, you would re-install rockstor and import your Pools, Shares and Snapshots. We have setup for this and hope to improve further as the project progresses. Something close to this happened due to python package update that pretty much rendered parts of Rockstor useless. But because of the way we are setup for online updates, we were able to roll out an update and solve the problem with little friction.