Re: RAID 5
If you can verify that the Reds can run in RAID mode 0 or 1 with striping they will 99.9 sure also run RAID 5 on the same controller.
Meaning you have to verify this yourself so you can get a refund, if the drives don’t work, why you can NOT trust anything WD claims you MUST verify the controller/NAS drive combination yourself in a working environment best with a lot of files on it (more than one million files is best) (and best to buy the drives in one go so you fill your enclosure(s)/NAS to (hopefully :)) get the same firmware(FW) version in the drives (you risk getting nasty hard to find failures if you have more than one FW version connected on the same controller)
If you are going the NAS way I suggest you to contact the NAS manufacturer and get a confirmation from him that the Reds can run in all the RAID mode(s) that you need and access the manufacturer userforum so you can get info from other users as to which drives work reliable on the RAID controller(s)/NAS model.
Also be warned that RAID 5 (apart from lower performance compared to 10 (mirroring with striping)) can take like forever to rebuild (severel days if you have big raid) and you risk that one more drive fail before finishing rebuild and you loose your data.
I have also used RAID 5 but reverted to run RAID 10 and use a not so powerful (cheaper) controller or NAS and spend the money saved on more drives (Sure WD really likes this suggestion) cause the RAID 10 is simpler and thus more reliable in the long run +many NAS runs “smoother” with RAID 10 than 5 but you have to verify that for your NAS.
Murphy’s law for RAID also dictates if a RAID 5 fails it will fail on 2 drives (before rebuild is finished) and if A RAID 10 fails it will fail on only one drive :smileyvery-happy:
Also if you are running with a hot spare (drive) that RAID will only fail when you try to add the spare drive to the array to gain more space 
A joke apart from it has actually happened to me with a RAID 5.
Personally I would not buy any WD NAS but go for Synology (not QNAP the have (?had) problems when you reach a high number of files, look in QNAP forum) why they have a bigger user base and most times answers and gives a solution if you contact their support. That is NOT the case for WD even if you have spend a small fortune on their RAID Edition drives, you will have to support yourself and/or use this forum where there luckily is some very skilled people (like ex. fzabkar)
Re:
“3D Active Balance Plus — Our enhanced dual-plane balance control technology significantly improves the overall drive performance and reliability. Hard drives that are not properly balanced may cause excessive vibration and noise in a multi-drive system, reduce the hard drive life span, and degrade the performance over time.”
I bet if you buy a 10 pack of Reds like 30 to 50% of them will vibrate, its an old problem for WD also for their RE series drives, but must confess that I have not tried a RED.
Re:
“RAID-specific time-limited error recovery (TLER) — The drive limits the ‘hang’ experienced on a read error in order to avoid a RAID controller considering the drive dead / offline.”
The big question here for me is if the TLER implementation is done so you can use Reds on a RAID controller (ex.Areca) or just made so you only can use Reds in a NAS that is certified to work with the drive.
In principle If you must use a RED for “desktop use”, the controller (on the mainboard) must be set to run in RAID mode (you can not disable TLER on Reds) but I must confess I don’t know if ex. Intel ICH will have TLER enabled if you set it to RAID in bios and just run one drive in one array, so you can boot OS from it . (some MBs must have 2 harddisk drives connected for BIOS to show RAID “menu” even if you just want to use one drive)
But we don’t know cause WD (as usual) don’t tell exactly where you can use or not use the Reds, and basic data like if or not the drive is designed so it must operate in a environment where there is an air flow or can live with no ventilation is(as usual :)) not specified.
So why do I still buy WD drives ?
Simple I am forced by the fact that there effectively is only two 3 1/2" Harddrive manufactures left in the world, WD and Seagate.
But I have seriously considered to upgrade to a 1 gig connection (have opticfibre to ISP) and use a cloud based serverservice but still it will take some time to transfer like 10 TB of data over the net and I suspect that I will have to pay premium for the 1 gig connection and the (cloud)storage provider.
