PRO 6 & WD EARZ drive compatibility

Drives not on the compatibility list may/may not work. If you have issues with drives not on the list NetGear will deny support.

There are three ReadyNAS platforms: Sparc, ARM and x86. All have very different hardware and a different Operating System/firmware. You may have noticed the Duo/NV/NV+ (Sparc) use RAIDiator 4.1.x or earlier, the Duo v2 and NV+ v2 (ARM) use RAIDiator 5.3.x and the NVX/Ultra/Pro (x86) use RAIDiator 4.2.x.

The WD20EARX is qualified for Sparc and ARM ReadyNAS units.

It is not qualified for any x86 model.

This could mean one of a list of things such as:
1. Disk hasn't been tested on x86. May/may not work.
2. Disk has been tested and there are compatibility issues

Whatever the reason this doesn't change the fact that NetGear will deny support if you run into problems using disks not on the list.

NetGear used to have a single list, but with the wide range of models with very different hardware it became impossible to maintain a single list due to the varying needs of different models.

mdgm wrote:
... This could mean one of a list of things such as: 1. Disk hasn't been tested on x86. May/may not work. 2. Disk has been tested and there are compatibility issues ...

Yea I understand. However here are some concerns that I have with the list. The hardware compatibility list includes the EADS and the EARS which were the previous versions of the drive. You can't find those now. The note for the drive says that only drives of a certain firmware, ones with 512kb sectors can be used. However if you view the tech bulletin, the 4k sectors of the other firmwares were officially supported in RAIDiator 4.1.7 released on November 12, 2010. That's over a year ago. I inferred, maybe wrongly, that the only reason there was a restriction was because of the 4k sector size. The EARX is basically the same drive as the EADS and the EARS, albeit with an updated interface. This is why I was really looking for an authoritative response from Netgear support (you're still Infrant to me though). If they say EARX drives are not supported I'll get other drives.

For x86 models, the firmware supporting 4k sector drives is 4.2.12: http://www.readynas.com/RAIDiator_x86_4_2_12_Notes

Now the Pro 6 was released late 2010 so it would have always come with firmware supporting 4k sector disks. So essentially the 4k sector issue is no longer relevant unless you were migrating the disks from an older x86 model (e.g. NVX, Pro). Having said that if you were to purchase the WD20EARS or the WD20EADS I would stick to the model specified in the notes.

Do also note that there could be under the hood differences or other differences in the way the drives work that may not be noticeable to an end-user using the drive as a single disk in a PC, but do make an impact to the drive's use in a RAID array. The NAS has to control things like disk spin-down etc. which a green drive would normally want to control itself. Regardless of whether the disk isn't on the list due to a compatibility issue or because it hasn't been tested NetGear can't support drives not on the list. If the disks haven't been tested they may have unknown problems that NetGear can't be expected to deal with or if they have been tested may have issues that prevent them from working.

Now regardless of this, I suggest you backup important data primarily stored on your ReadyNAS regularly e.g. to your NV. After all RAID is not a replacement for a backup.

Fair enough. Since the drives work and I only have two, I'm going to keep them in for the time being. I'll wait for prices to come down on the enterprise class drives before swapping them out.