Advice for upgrading without backup data for big NAS config

Hi,

I've installed a FreeNAS 9.2.1 and i'm wondering if i should upgrade it to 9.2.1.8 ?

As my NAS has 24 TB total disk capacity, i can't follow the bold sentence in the FreeNAS 9.2.1 guide (section upgrade) : "Before performing an upgrade, always backup your configuration file and your data"

i can save my configuration file but not my data I'm using a NAS in order to store data from my computers... i haven't another NAS to backup my first one during upgrade...

A) so,...

Advice for upgrading without backup data for big NAS config