> NAS is using an external harddrive enclosure over USB.
The N in NAS means "network" as in network attached storage so it's not a NAS.
> really curious about how wise such a NAS setup is?
For data use cases like this, USB 3 can be reasonably comparable to Thunderbolt 3, and that connection is generally faster than the media.
This use case seems to be using the external device as a continuous external backup rather than as network attached storage, which is a great use of USB-C dongle SSD enclosures that are the same size or larger than the SSD inside the laptop.
You effectively have mirroring as well, since you have both the internal SSD copy and the external SSD copy, in different makes and forms, unlikely to both fail.
How I interpret the setup that OP has, is that he some computer (a PI, an old laptop, a NUC, etc.) which is connected to drives in an external drive bay through USB. This is a somewhat common setup and is definitely a NAS.
> For data use cases like this, USB 3 can be reasonably comparable to Thunderbolt 3, and that connection is generally faster than the media.
External HDD enclosures can often contain 4 drives. During a resliver all of these could be heavily accessed. I'm not sure how the single USB 3 connection fares in this scenario. In a normal desktop you'd have four separate SATA connections, and even then resilvering a large RAID setup can take quite some time.
In the context of the grandparent, a "NAS" is a device, attached to the network, that provides storage. How the storage the NAS provides is connected is irrelevant.
On a related note, I can't think of any drive that has a network interface instead of something like USB, Firewire, Thunderbolt, SCSI, IDE, etc. so how exactly would you define a NAS device?
The N in NAS means "network" as in network attached storage so it's not a NAS.
> really curious about how wise such a NAS setup is?
For data use cases like this, USB 3 can be reasonably comparable to Thunderbolt 3, and that connection is generally faster than the media.
This use case seems to be using the external device as a continuous external backup rather than as network attached storage, which is a great use of USB-C dongle SSD enclosures that are the same size or larger than the SSD inside the laptop.
You effectively have mirroring as well, since you have both the internal SSD copy and the external SSD copy, in different makes and forms, unlikely to both fail.