Western Digital just expanded its WD Red and WD Red Pro hard drive lines for NAS boxes with new 10TB capacity models. Both are helium-filled HDDs featuring WD's fourth generation HelioSeal technology.
The Red and Red Pro lines are purpose built for always-on NAS appliances with up to eight drive bays (Red) or 16 drive bays (Red Pro). They're tested to withstand the higher temperatures that can sometimes be attributed to NAS environments and also features safeguards against increased vibrations inherent in multi-drive systems.
WD's new 10TB models both sport 256MB of cache (the product pages erroneously list 128MB, but the correct amount is listed on each one's specific sheet). The difference between the Red (WD100EFAX) and Red Pro (WD101KFBX) models is the spindle speed—the Red drive spins at 5,400 RPM while the Red Pro operates at 7,200 RPM for a bit of added performance.
The Red line has proven popular over the years, with WD having shipped over 16 million Red family HDDs to date. It's also shipped more than 15 million helium-based high-capacity HDDs so far.
As to reliability, cloud backup provider Backblaze seems to have had pretty good luck with WD's Red line, though the sample size isn't very large. Backblaze's latest reliability report shows no failures out of the 46 4TB Red models it deployed, and just three failures out of 443 6TB Red models.
WD is charging $494 for its 10TB Red, which is backed by three-year warranty, and $533 for the Red Pro, which features a longer five-year guarantee.