Non-RAID backup volume - advice needed

Synology
1

I’m using DS920+. When I set my NAS with 4 drives, I made 1 data volume with 3 disk in RAID 5, and 1 backup volume(local backup) with non-RAID. This made backup volume as single point of failure. (I have proper offsite backup with external HDD btw)

Currently backup volume houses all of my local hyper backup, active backup, and some snapshot replication for important shares.

I will ultimately do one of following:

  • Buy cheap, 2-bay NAS to house backups, with RAID 1.
  • Buy DX extension unit and house backup there with RAID 1. (Although many slots will be empty, but they will be filled eventually, I think.)
  • Upgrade to 5-bay NAS and make local backup RAID 1.

However, I can’t afford solutions above right now, so I need some temporary measure. I’m using WD Red Plus 8TB for backup volume, which just passed 3 years of operation time.

How can I mitigate this potential failure? I saw some people use dd to clone entire disk, but I also heard that it’s not 100% reliable.

P.S. Am I hyper-reacting on this?

2

Backups are always and only off-NAS. What you have done is false assurance. Use an external USB drive in its place.

3

It’s complicated to say as whole. My backup disk(volume) holds:

  • NAS data volume backup. (This is same-NAS diff-volume. Problemetic, but it works for now.)
  • Some shared folder snapshots from data volume for failover.
  • Active backup data. To my PCs, it’s proper backup.
  • Manual backup data, like external HDD, low-priority data that not requires versioning, from my PC(AI model files, for example). It’s proper backup.

And they get synced or backed up to external HDD(USB) in regular basis.

What I need to know is good way to approach to my problem though.