Replace 3TB disk with 500GB Disk...

[diaakhalil]

Dear All,
I have TrueNAS, I created 2 pools, one for the system and one for the data... the data pool contains one 3tb disk, but I found out that it is too much space and waste of hardware resources, so I need to replace the 3tb disk with 500gb disk without loosing any data...
What are the options I have to solve this issue???
Thank you All in advance...

 

[VioletDragon]

You will need to backup then restore the data or you can create a new Zpool with the 500GB drive then move the data on the Server itself.

 

[Heracles]

In all cases, a single drive pool (so a single drive vDev) makes no sense for ZFS and redundancy. You should go at least with 2 drives for a mirror.

Also, do not forget that no server can be more than a single point of failure and that backups are mandatory for anything you are not ready to loose right away.

 

[danb35]

You will need to backup then restore the data or you can create a new Zpool with the 500GB drive then move the data on the Server itself.

That shouldn't be necessary. Add the second drive as a new vdev to the pool, then remove the first. The system will evacuate the data to the new disk and then offline the first. The question is whether you'll be able to do that through the GUI, and I'm not sure whether that's the case. But it surely could be done at the CLI.

In all cases, a single drive pool (so a single drive vDev) makes no sense for ZFS and redundancy.

Universal statements nearly always have exceptions, and thus are incorrect. For just two examples, ZFS still gives you snapshots and checksums--it can't correct data corruption, but it can at least detect it.

 

[Heracles]

When talking to someone who is still on his first post, I consider he is not ready for corner cases and that to learn the basics is million time more important. It was the same here where the new user was considering Raid-Z1, this one about using snapshots as backups or this one about turning dedup On.

Only once the basic learned that corner and extreme cases can be considered. Exposing new users to that kind of ideas only comforts them in their choice of not respecting the basics and at the end, they loose it all.