I have 4x 6TB Reds in the raid (3x 256MB cache and 1x the old one with 64MB cache in the Synology NAS). So SMR and CMR are mixed, which is not so great in a raid network. SMR is not at all suitable for Raid and ZFS -> rebuilds are always a risk. SMR and CMR should not be mixed anyway, I hope WD has a solution ready here and exchanges the disks - absolutely useless in the NAS. At Seagate, the Barracudas with 2/4/8 TB are also with SMR and it was not pointed out.

Sure, that works without any problems. The main difference is that the Red series was explicitly designed for continuous operation, for example in a NAS. But you can run them just as well in a PC.

Hello Nlongatt, I don't think this will work. This hard disk is intended for a server. Namely for the NAS server from Synology. I needed the hard drive for this server.

If the two existing hard drives are installed in a NAS that can hold 4 drives or more, then this should not be a problem. The WD40EFRX-68N32N0 have SMR and the selected WD RED also. That should fit.

This is a full size bare disk drive for desktop computers or servers. To connect it to a laptop you would need something like a SATA to USB adapter/cable, but this would normally be used only in exceptional cases such as recovering content or similar.

So they definitely fit. However, I can't say much about the volume - my NAS is quite quiet, although I didn't pay much attention to it when I bought it. Basically, NAS always have a certain noise level.

I believe the EFRX model is listed as compatible but you can check it yourself here - https://www.qnap.com/en/compatibility/?model=70&category=1

Had the same issue three times with the 4TB drives, replaced them each time by a new one to be sure. On another NAS (both QNAP / raid 5) and 6 TB drives, no issue for yet 4yrs. I even wondered if it is not the NAS (TS-451) creating the issue... Better safe than sorry as they say.

Because this is the new version with SMR, see 'Important notes', and that's probably why demand has collapsed. The one with the small cache is still the old, "good" one.

Clearly upgrade.

A NAS is nothing other than a PC in continuous operation in a somewhat narrower housing. The decisive factor for RED disks is continuous operation. So yes, it can be installed. However, I would put the OS on an SSD and you would also have to have a backup strategy in this setting to protect yourself against failures, but that has certainly already been taken into account in your considerations.

WD40EFAX is the latest version of 4TB capacity and it has 256 MB cache. Whereas WD40EFRX is the previous version with 64 MB cache. WD40EFAX is faster than WD40EFRX. However, I find WD40EFAX (new version) a bit louder/noisier than the older version.

In principle, yes.

I've noticed that too.

Thank you very much for pointing this out! We will have this adjusted immediately.