My recommendation: Don't use ReadyCloud user home shares

There is so much to say...

Don't use ReadyCLOUD locally.

ReadyCLOUD is not a business grade service, it's a free feature. Look at prices of Cloud services for Pros, you'll see the difference. So downtime is "acceptable". (I'm obviously NOT saying the ongoing issue is acceptable!)

Don't confuse RAID redundancy with backup.

Don't expect that multiple disk failure can't occur.

Don't confuse snapshots with backup.

Don't confuse a resilient backup with an easy-to-restore-from backup.

Nothing replaces an external backup.

Don't assume your backup is ok, check its integrity.

Bidirectional syncing Is not a backup, it's quite the opposite, the surface of vulnerability is increased.

Unidirectional syncing is also dangerous as any accident on the source may be replicated on the destination.

Don't leave your NAS run for 5 years without keeping an eye on the health of the hard drives.

The best solution is not necessarily the one that protects you from everything, it's a balance between resiliency, efforts and money.

Ask yourself the right questions:

How important is the data?

Am I protected against accidental file deletion, accidental file modification, accidental share deletion, virus and ransomware, reasonable hardware failure (eg. one disk), catastrophic failure (multiple disks, chassis), catastrophic situation (fire, theft), software failure (NAS doesn't boot, filesystem corruption), bit rot, etc.

Is resiliency or ease of recover the most important for my backup? Or both?

Do I need high availability (eg. data loss is not important but availability of workspace is)?

How much money, time and effort do I want to put in my backup plan?

I designed my backup plan as an exercise, which somewhat justifies its relative complexity. Sharing here some details as an example. Availability is not a concern for me and wasn't talen into account in the design.

- I have two NASes, each from a different manufacturer, to lower the risk of impact of a software issue on a NAS.

- On each NAS, I use a different filesystem, to lower the risk of impact of an issue related to filesystem.

- Some of my devices transfer their backups to one NAS, some to the other one, to reduce impact of a failure of a NAS before further propagation of backups.

- Daily, the first NAS mirrors the data from its devices to the second NAS, then the second NAS mirrors the data from its devices to the first one, to lower the risk of impact of a complete NAS failure.

- On the second NAS, I use snapshots for versionning of the backups. Because I use mirroring backup tasks, this is required to allow rolling back if a bad backup is propagated to the other NAS.

- On the first NAS, the most critical data is backed up to a Cloud location, to allow easy recovery, increase resiliency while keeping the amount of data low enough to fit in a free Cloud service.

- On the second NAS, fortnightly, the content of the shares and snapshots are copied to a BTRFS USB drive (previous snapshots are retained, it's a cumulative task, not a mirror task), to lower the risk of impact of a catastrophic event.

- On the second NAS, fortnightly, the content of the shares is copied to an EXT4 USB drive (rotating backups to know the exact content of a share at a point in time and also allow versionning), to further lower the risk of impact of a catastrophic failure, as well as reduce the impact of a flawed backup method (bad script, etc.).

- The USB devices are not stored in the same location as the NASes, and I don't use them the same week, so I always have a USB device containing my backup at the other location in case of a catastrophic event occurring during the backup of USB task.

- The NASes are not beside each other, to reduce the probably of a localized issue impacting both.

- The first NAS is behind a UPS, to prevent power issues to damage its hardware or corrupt its software.