Verdict

For a NAS or any RAID array, the ST2000VN003 is the clear pick - it's a CMR drive, while the ST2000DM008 uses SMR recording, which is not recommended for RAID. Only consider the ST2000DM008 for single-drive or archival use.

ST2000DM008 ST2000VN003
Capacity 2 TB 2 TB
Recording tech SMR CMR
RAID / NAS safe No Yes
Class Desktop NAS
Spindle speed 7200 RPM 5400 RPM
Cache 256 MB 256 MB
Noise (idle) 22 dB -
Fill Air Air
Interface SATA SATA
Failure rate (AFR) - -
Price / TB $54.92 $89.54

Highlighted cells mark the stronger spec for a NAS build. Failure rates from Backblaze Drive Stats where available; $/TB shows once live prices are wired.