Ready to expand a 2-drive mirror with 2 additional drives... Upgrade before?

[Macaroni323]

I have a simple data pool on 2 4TB drives in mirror that were created with FreeNAS-9.3 a couple years ago. This pool has lived through many updates to the OS and is currently on FreeNAS-11.0-U4. There was even a failed upgrade early in FreeNAS-9.10 that resulted in a reinstallation or FreeNAS-9.10 and import of the pool and recovered configuration that worked well. Now the system is on FreeNAS-11.0-U4 still with the 9.3 feature flags and I'm ready to add 2 more 4TB drives to attempt to expand the pool. I am wondering if it would be better to upgrade the pool to v11 features before adding the drives to the pool? I am extremely green at FreeNAS and I'm not really sure about the method for adding disks to the pool either. I was thinking of setting up the new drives as a mirror and striping the two mirrors together if that's possible.

 

[gpsguy]

Sounds like a great plan.

Read the section on extending a volume - http://doc.freenas.org/11/storage.html#extending-a-zfs-volume

I was thinking of setting up the new drives as a mirror and striping the two mirrors together if that's possible.

 

[garm]

Yup that’s the way I would do it ^^

 

[danb35]

I am wondering if it would be better to upgrade the pool to v11 features before adding the drives to the pool?

You probably should upgrade the pool, but there's no real urgency to do so, and no particular reason to do it either before or after expanding the pool.

 

[Macaroni323]

Thanks, I'm currently refreshing my backup of the pool and will report back after I'm finished.

 

[Macaroni323]

OK... The pool is now twice the size after adding 2 new 4TB drives to the original 4TB drives in mirror. I used the volume manager and all seemed to work OK but I am not sure if the RAID functionality is RAID10 or not. I didn't notice any resilvering going on so I might have ended up with 2 mirrors in a sort-of JBOD. Not sure.

 

[danb35]

not sure if the RAID functionality is RAID10 or not

Not precisely. Data is dynamically striped across multiple vdevs, when multiple vdevs are part of a pool. That means that, when a new vdev is added (which you just did), new data is written more to the new vdev, but existing data isn't rebalanced across the vdevs.