Built new Scale NAS to Replace FreeNAS, best way to get the data online?

[HeloJunkie]

So, as the title says, I have built a new TrueNAS Scale system (two actually) to replace two older FreeNAS systems I have outgrown. I am replicating one of my datasets (140TB) to the new system. For now, I just created a dataset called `snapshots` on the new system and set up a replication task to grab a manual snapshot that I did and drop it there.

Once that replication task is completed, I want to take that snapshot and create a new dataset on the new system with the data. I THINK I just need to clone the snapshot, but as I recall, that means I can never delete the snapshot that the clone was created from. Is that correct?

If I want to be able to delete that snapshot, what would be the best way to move that data into the new dataset?

 

[NugentS]

I would have thought.
1. Break the replicaction task (aka delete it on sending machine - I am assuming you are doing a push here)
2. Make the datset read/write rather than RO (remove readonly flag)
3. Rename the datset to whatever you want it to be /mnt/PoolName/DatasetName (or more levels down if you want
4. Done

A snapshot is a set of pointers, it is not the data, it points to the data. When you replicate a snapshot it copies all data that the snapshot references. [Not sure how to write this better]

If you clone the snapshot - you will need the same space again - but by renaming it - you don't need more space

 

[HeloJunkie]

I am actually doing a pull, but same result. I marked it as not read-only when I did the replication task. So I am not going to end up with a snapshot on the new system, it will just be the actual data itself? Is this because I replicated into an empty dataset?

 

[NugentS]

Just remember to delete the replication task once finished with as it, depending on settings may bugger things up / fill up the disk if you run it again.

On the new system you can delete all the snapshots, which will leave just the base data in its latest form

 

[HeloJunkie]

Will do, but I think I still have a question on the replication of the snapshot automatically being available, is this because the snapshot was replicated into an empty dataset? When I normally replicate snapshots they don't behave in this manner.

And one other quick question, I did a manual snapshot of the dataset, I am replicating that, but there have been other changes to the dataset since I started the 140TB replication. If I do another manual snapshot of that dataset and then run the replication again, will it only send the changes or will it not work that way?

 

[NugentS]

The usual way of achieving what you are trying to achieve is as follows:
1. Replicate a snapshot - takes a long time
2. Create new snapshot
3. Replicate new snapshot
4. got back to 2 and repeat till you get bored / not much happens
5. Freeze the source dataset (maybe make it RO or turn off the apps that can update it / unshare the dataset - whatever)
6. Create new snapshot
7. Replicate new snapshot - this should occur very quickly

Now the data is up to date on the new location - so with it what you will. All the snapshots are there - but if you delete the snapshots on the destination dataset - you just get left with the latest version of the data

 

[HeloJunkie]

OK, so when I replicate the second/third/forth snapshot, do I need to do anything at all to them once they have been replicated or will they just become available at the dataset even though there is now data from the first replication there?

Sorry, I have never had to replace an entire server before and I appreciate the help!!

 

[HeloJunkie]

but if you delete the snapshots on the destination dataset - you just get left with the latest version of the data

I don't think I understand this, so I need to leave all the snapshots on the destination system (which is going to be the active system eventually) or I am just left with whatever few files changes during the last snapshot, or if I delete the snapshots I will have 100% of my 140TB of data but as it was at the time of the last snapshot with no ability to rollback or go back to previous snapshots?

 

[NugentS]

"if I delete the snapshots I will have 100% of my 140TB of data but as it was at the time of the last snapshot with no ability to rollback or go back to previous snapshots?"

This - but nothing to stop you making new snapshots, on the new system

 

[HeloJunkie]

"if I delete the snapshots I will have 100% of my 140TB of data but as it was at the time of the last snapshot with no ability to rollback or go back to previous snapshots?"

This - but nothing to stop you making new snapshots, on the new system

Understood, that makes perfect sense! Thank you so much for the great information.