WD Purple 4TB Surveillance Hard Disk Drive @Newegg $94

Just get WD Reds for cheaper.

Quote from karazi : Just get WD Reds for cheaper.

red might be fine for camera system dvr, but purple is meant for 24/7 writes.

Quote from karazi : Just get WD Reds for cheaper.

You can point to a WD Red CMR drive currently available for less than this purple drive?

Quote from Danimal86 : red might be fine for camera system dvr, but purple is meant for 24/7 writes.

its the other around!!
source:https://www.gamersnexus.net/guide...ed-in-2017
WD Red Best Uses (Network Attached Storage)
Although not for gaming, the commonness of home based cloud storage, SOHO environments, RAIDs, and server investments make the WD Red line worth mentioning. GN uses three WD Red 2TB disks ($86) for its own RAID 5 setup on its render machine, which we chose for their affordability, density, and reliability in RAID.
Distinguishing WD Reds from their desktop counterparts is that they are built to withstand the challenges of the always-on NAS environment. NAS drives are built to endure the constant vibrations and thermal envelope inherent to multi-drive systems.
Previously limited to a 6TB capacity, the WD Red line is headed by the newest 8TB model ($330). Western Digital uses their HelioSeal technology to fill and seal the drive with helium. Helium is lighter than air, and its purpose is twofold: it allows the chassis to accommodate an extra 1.2 TB platter (7 total), and it allows for less turbulence and resistance equating to less power draw and heat. Observing the above table, users can see the WD Red series sport load/unload cycle ratings twice that of the other drives, offering a glimpse into the expected service life.
The WD Red 8TB uses 14 read/write heads, an LSI-based controller in conjunction with 128MB of cache, has RAID error recovery controls, NASware 3.0, and comes with a 3-year warranty.
WD Purple Best Uses (Surveillance, DVR, NVR)
WD Purple is Western Digital's surveillance class storage. These drives are suited for 24/7 usage and the firmware and caching algorithms are optimized for write intensive applications, as these drives spend most their service life writing. The 4TB WD Purple drive is $135, illustrating the price/capacity focus of the Purple drives.
Exclusive to the WD Purple series is AllFrame technology. By reducing errors, pixilation and video interruptions, AllFrame attempts to reduce video frame loss. WD Purple also features TLER and support for the ATA streaming command set.
WD Purple drives can support up to 8 drive bays and 64 HD cameras, have an annualized workload of 180TB/year, and come with a 3-year warranty. Because these drives write and erase data endlessly, the higher annualized workload becomes important.

8TB not a sale