At the end of last year, Western Digital launched a new line of HDD's, specifically made for use in NAS devices. The new disks got the moniker 'Red', and became available with capacities of 1TB, 2TB and 3TB (click here for our review of those disks). Today, Western Digital launches the missing link in this mini line-up, the 4TB model. We obviously put it through its paces rightaway.
The WD Red 4TB is specifically developed with the use in NAS devices in mind, so you shouldn't use it in a desktop PC. Western Digital claims that the disks have been optimised for a usage scenario of 24 hours a day, 365 days a year thanks to the NASWare firmware. In order to improve the life span in NAS devices, Western Digital reportedly developed a technology that makes it possible for multiple disks in a single array to work at slightly different speeds (RPM), so that the resonance one disk causes doesn't bother the other disks.
Whether special NAS drives really work for a longer time compared to regular disks when you install them in a NAS device, is difficult to prove, but there certainly are some advantages. When we reviewed the other models in the Red line-up, it became clear that they are tuned to produce as little noise as possible, and to keep the power consumption down.
The most important advantage of the Red disks is actually something these disks don't have but regular disks do. When a normal drive registers a read or write error, it keeps on trying to process the data for a while. During this time, the disk doesn't accept new instructions, and as such doesn't appear to respond. The result is that many NAS devices consider the disk to be defective, and exclude it from a RAID arry. It can take quite some time to get the disk back into the array. This obviously is something that you want to avoid in NAS devices.
The Red disks take less time to solve the problem resulting from a read or write error. In this way, the NAS device doesn't have to categorise the disk as defective. It may try to carry out the same instruction again, or in the case of a RAID array may choose to read the data from a different disk or write to a different disk. Western Digital calls this TLER (Time Limited Error Recovery). If you don't have Red disks, it is possible to utilise TLER though. Western Digital has a special tool that works on most regular disks.
A further advantage of Red disks is that Western Digital specifically tests them in NAS devices. This reduces the likelihood of incompatibility with NAS devices of the major brands.
Western Digital Red 4TB
The Western Digital Red 4TB clearly belongs to the same family as the other Red disks. It obviously is a 3,5" model, and it is also based on 1TB platters (four of them). Western Digital doesn't make any official claims about the rotation speed, but calls it IntelliPower. The average rotation speed is about 5400 rpm. The interface is Serial ATA 600, and the disk works with a cache of 64 MB. The warranty is three years.
The price of the new disk isn't available yet. However, the price per gigabyte of Red disks decreased quite a bit lately, and is just a tad above the price per gigabyte of normal desktop disks.