Check that they’re actually 8tb. Usually when drives that cheap are opened up, it’s USB sticks that have custom firmware to pretend to have 8tb, and you’ll really only have something like 8gb. It’ll overwrite the data as you keep writing to it, so you may not notice it until a while from now. Even if they feel heavy. Some of them have weights added to throw you off. Take a look at https://www.reddit.com/r/pcmasterrace/comments/9wimlo/when_you_buy_a_cheap_external_ssd_from_china/

(Sorry for the reddit link, but that’s where the images are)

SMART Stats?

It’s like buying a car and asking “did a get a good deal” without stating anything about the car.

Definitely check SMART, but don’t post it here per Rule #9. Post at r/techsupport

9. r/techsupport exists.

r/Datahoarder is not a sub for tech support,

r/techsupport is for posts which could have been a google search, e.g. a post with CrystalDiskInfo screenshots with the title “is my drive ok?”. Literally every question about SMART status*. Audio recordings of “is this click noise normal?” More technical questions are allowed, e.g. “what is the optimal ZFS configuration of a 24 disk array” or “how else can i automate the archiving of this [thing]”*