4 of these drives good for 32tb 24/7 dlna nas server? Don’t want to beat a dead horse here... Really it’s just to stream my 10Bit 4K movies using DLNA

It all depends on what size and what RAID configuration you are asking about. Most people would be using RAID 5 or something like Synology's SHR (similar to RAID 5 but doesn't require equal size hard drives) for this purpose. If you are thinking that 4x8TB will give you 32TB of storage that is not correct in RAID 5 because of the overhead used for data protection. It works like this for RAID 5, 4x8TB = 24TB storage, 4x10TB = 30TB storage, 4x12 = 36TB storage. So first determine which RAID configuration works best for you and then find a RAID calculator available online to choose your RAID configuration and hard drive size. If you just want speed, with no parity checking then you could go with 4x8TB or 2x16 TB (whichever is cheaper) in RAID 0 for 32TB of storage but file corruption could be an issue and there is a possibility that you can only do 2 hard drives in RAID depending on your hardware. Having said all that, these drives will certainly stream 4k 10-bit HDR movies over DLNA. Streaming 4k is just as much up to the software and hardware of your computer than it is the hard drives. A nicely configured Windows machine, for example, may stream them fine however a less powerful NAS device may not. There are a lot of moving parts but these drives will not be an issue. There are also issues with playing the 265 codecs in Windows 10 Media Player but the same files that will not play in Media Player, will stream via DLNA to my LG TV just fine and play in full 2160p HDR with no problem. These same files will show up fine in my 9 year old NAS but will not stream via DLNA on it but photos stream fine. So it all depends on your exact configuration. But the drives are fine. If it all gets too hard then just get a fast (say 400 MB per second) USB stick and copy 10 movies at a time on to it and plug it into your TV. The Samsung BAR Plus 256 GB works well for this in my experience. You can also look into getting streaming server software on your computer and a client connected to your TV.

What is the difference between this and the WD Black drive?

The Red is engineered for 24/7 usage. The Black is not.

Is the red wd drives better for cctv/nvr in raid setup than the purple drives? i hear purple drives are not lasting long. both red and purple are 24/7

I use my purple drives with 9 cameras 24 x 7 and have over three years without a single failure. pretty good if you ask me.

Can I use this as an external storage for my desktop?

I have four of the earlier 3tB versions of this drive in external USB3 enclosures and use them in rotation for critical full system backups. They have served very well in that capacity. I also have one of the 3tB drives in my main daily-driver computer now and it does that quite well although it isn't as fast as some but since it is used mostly for secondary data store it doesn't matter so much. The reason that I have so many of the older 3tB drives is that I upgraded all of the drives in my Drobo NAS to 6tB drives a while back. Those drives as well as five of the 8tB units in another NAS have worked perfectly so I can highly recommend them (for the proper use, of course).

Brand	Western Digital
Product Dimensions	14.71 x 10.16 x 2.62 cm; 716.68 g
Item model number	WD4003FFBX-SPMU3N0
Manufacturer	Western Digital
Series	Red Pro
Colour	Black
Form Factor	3.5-inch
Hard Drive Size	4 GB
Hard Disk Description	Solid State Hard Drive
Hard Drive Interface	Serial ATA
Hard Disk Rotational Speed	7200 RPM
Number of USB 2.0 Ports	1
Voltage	1 Volts
Wattage	7.2
Are Batteries Included	No
Lithium Battery Energy Content	2 Kilowatt Hours
Lithium Battery Packaging	Batteries packed with equipment
Lithium Battery Weight	2 g
Number Of Lithium Ion Cells	5
Number of Lithium Metal Cells	5
Item Weight	717 g
Guaranteed software updates until	unknown

Red Pro 4TB NAS 3.5" Internal Hard Drive - 7200 RPM Class, SATA 6 Gb/s, CMR Recording Technology, 256MB Cache

Details

Description

Specifications

Common Questions