Degraded Vol 1 HD - RAID 1 (mirror) 2nd drive

Hi all,
I have a PR2100 NAS drive that I use as a server. It’s a RAID 1 with 2TB in each drive bay (2 drivebays). Last Friday the server locked up so I rebooted, but the drive health says that volume 1 is degraded, so I assume this is the HD in drivebay 1. I have purchased an exact replacement (WD RED NAS HD 2TB), but I can’t find any information on how to replace the HD. I assume that since this is a mirror volume 2 will write back to the volume 1…just a guess or do I need to back up all of the HD (1TB of data) and rebuild…ugh…it seems this should be pretty easy and straightforward to replicate the volume 1.

If you have a PR2100 then you don’t own the 2nd generation OS5 WDMYCLOUD.

You need to go back to the Community and post in the, My Cloud Pro series topics if it’s OS5.

If it’s OS3 then see the correct topics for the PR2100 under OS3, My Cloud Pro Series.

WD My Cloud Pro Series PR2100, NAS Hard Drive Store | Western Digital


Replacing a degraded hard drive in a RAID 1 configuration should be a fairly straightforward process. Here are the general steps you can follow:

  1. Power down the NAS device and unplug all cables.
  2. Open the device and locate the degraded hard drive.
  3. Remove the old hard drive from the drive bay and replace it with the new one.
  4. Reassemble the device and plug in all cables.
  5. Power on the device and wait for it to fully boot up.
  6. Access the device’s web interface and navigate to the RAID settings.
  7. Select the option to rebuild the RAID array using the new hard drive.
  8. Wait for the rebuild process to complete, which could take several hours.

Since you have a RAID 1 configuration, the data from the working hard drive should automatically be copied to the new hard drive once it is installed, without any need for you to backup and restore the data manually. However, it’s always a good idea to have a backup of your important data in case something goes wrong during the rebuild process.

Worked Perfectly! It took more than 3 hours to rebuild, but thank you for the reply.