Upgrading the disks size of a RAID-Z2 vdev

[AlainD]

Hi

I'm starting to build a freenas home server (mostly for backups and a little bit central storage).

For safety I would use 6 disk RAID-Z2, but I would test with a few smaller disks included (2x 2TB, 2x 1.5TB and 2x 1TB).
I know that I won't use the full disk capacity, but that's fine for a start and certainly for tests. Aprox. 4TB will give enough room to start and run the server for quite a while, but I expect it to grow to apporx. 8TB (6x 2TB in the future).

Are there "high" risks involved with "upgrading" the disks with real data on them (and yes I will have a backup) or is this rather safe to do?
I know that I would "fall back" to one parity while upgrading the disk.

 

[cyberjock]

In the case you explained I'd feel relatively safe that I wouldn't have to restore from backups. Backups are always recommended but I'd feel pretty confident you won't be needing to use them.