Western Digital WD RE Hard Disk Drives (3.5 2TB 2000 GB Serial ATA III; 2000 GB; 7200 RPM; Serial ATA III, 64 MB)

This was a replacement for a failing drive and has worked well ever since.

working fine in NAS

I have used this drive in a RAID enclosure for a Mac Pro. When I install a new drive, I always burn them in for several days by writing large files onto the drive and run diagnostics, these drives pass with flying colors. They appear to be new-old stock units, they's come in a sealed static proof plastic drive and externally they look like they have not been previously used. And the price per drive is excellent.

5 year warranty.The head park cycle is 600,000 and the data is 550TB a year or 1.5 TB a day 365 this is running 24 hours a day. This is a much better choice for RAID or NAS as the magnetic error rate is 10^15 instead of 10^14 with NAS drives. NAS RAID 5 with 7 drives with one failing during rebuild as of the year 2009 the re-build would fail due to a magnet bit going bad causing a total failure of the rebuild and loss of all data. RAID 5 or 6 and enterprise drives suggest a solution. However large sized drives have a draw back when used as fast access, for example. we'll assign a value of 1 to a 2TB drive, a value of .5 to 4TB and a value of .33 to 6TB. What this represents is that if this is HOT data then to get to reoccurring data is a longer wait since the HDD is a serial device. To put numbers to this a pool of 1 (Pool1 2TB x4) is 85+ MBs at 70% full (older Qnap very small cache). Now if you were to make Pool1 + Pool2 + Pool3 your bandwidth would be 260+ MBs.

Good solid dependable drives. Replaced WD Black drives being used in a RAID array. Best part is the warranty - 5 years no questions asked. Just be sure you keep your original receipt. Otherwise, they use the manufacture date on the drive for warranty purposes.

I registered the drives and had a little issue reading the sn, but that was corrected. Drives work fine.