Migrating 2x3TB mirror to 2x8TB mirror

[KenNashua]

I currently have a pool with 2 2x3TB mirrors and is running short on storage. I have a new pair of 8TB drives.

Given that one pair is approaching 5 years, instead of expanding the zpool from 6 to 14 TB, it seems a wiser choice to replace the pair of 5 year old drives with the 8TB drives.

From the GUI, I can do this via the replace drive option. Does this do an actual detach so I have a copy of whatever is on the 1st half of the mirror should the one drive die during reslivering?

I'm wondering if it's safer to expand the mirror as follows (I don't believe the GUI supports this?)
attach 8TB#1, allow reslivering
detach 3TB#2,
attach 8TB#2, allow reslivering
detach 3TB#1

then I believe I have to export/import to get the vdev to auto-grow to 8TB, correct?

 

[DrKK]

http://doc.freenas.org/11/storage.html#replacing-drives-to-grow-a-zfs-pool

^^ This is the only method we recommend.

 

[KenNashua]

Thank you! Not sure how I missed that, it sounds similar if not the same procedure.

 

[Ericloewe]

Not exactly the same. Either method would work, but the GUI doesn't allow mirror vdev manipulation yet.