Clarifications required regarding snapshots and volumes

[-fun-]

Hi all,

I have a question for better understanding of volumes and snapshots.

I have a volume flospool/flospool/tmbackup/FlosMBP. As the name indicates this is a volume for Time Machine backups. Unfortunately this one got garbled somehow (from my Mac's point of view) and my Mac refused to add more backups. The volume is shared via AFP.

I cloned a snapshot of FlosMBP thereby creating the volume flospool/flospool/tmbackup/FlosMBP-clone2 and changed the AFP share to point to the cloned snapshot. After this my Mac was perfectly happy to use FlosMBP-clone2 as backup target. I also added a task to automatically create snaphots from FlosMBP-clone2 and removed the corresponding task for FlosMBP.

So far so good.

Now my questions:

1. I do not need the volume FlosMBP anymore. As far as I understand volumes and snapshots it should be safe to just delete this one. The new volume FlosMBP-clone2 should not be affected by this.

Is this correct?

2. After deleting the old volume I would prefer to have the volume FlosMBP-clone2 renamed to FlosMBP to match the name used before. What is the easiest / fastest way to do this?

I assume I can manually create a snapshot named FlosMBP from FlosMBP-clone2 and then delete FlosMBP-clone2. Right?

3. In case my volume gets garbled again: Is there a better way to set back to an old snapshot? In the guide I read about a rollback to a snapshot. However it has a warning regarding problems with replication tasks and a recommendation to rather clone the snapshot and delete again after restoring files. OTOH I do not currently have any replications running so this might be the better way? This is also relevant because I switch to the clone and would rather delete the old volume.

Anyway rollback options were not available in my case. Also the guide says that the rollback is possible only to the latest snapshot. Can I possibly rollback several snapshots the chain back in time?

Best Regards

-fun-

 

[depasseg]

Anyway rollback options were not available in my case. Also the guide says that the rollback is possible only to the latest snapshot. Can I possibly rollback several snapshots the chain back in time?

You need to delete the snapshots back to the one you want to roll back to (don't delete that one), then you can roll back. You should be able to delete the snapshots in FlosMBP and then roll back one more, to the good one, and then just destroy the clone. Changing a dataset name is not possible in the GUI, (it's possible using the CLI, but requires detaching the pool, using the CLI and then importing it via GUI).

And yes, the Clone is completely separate from the original, so you can delete either. I don't think the clone has all the snapshots though (I could be wrong).

 

[-fun-]

Thank you. I didn't think of this obvious solution (deleting snapshots backwards through time). I will check this next time. I'm prepared however.

 

[DrKK]

Right, just for clarity for anyone else that finds this post: For each dataset, there is only one immediate rollback available---you can rollback to the most recent snap. If you wish to roll back to an earlier snap, then you have to delete any snapshots which intervened since the one you want to roll back to.