The nice thing about this NAS is that should I need to access the files should the Pi crash and burn, it’s just a matter of plugging the HD into my computer. ryecoaaron suggested using systemrescuecd to access the EXT4 data.
And I suggested something different for a reason. Since representation of the data might be different. If you use an OMV installation as backup target for macOS clients for example the data on ext4 is in a totally different format compared to backing up to locally connected disks.
The most important information is this: TEST THIS NOW and not when it's too late (of course no one will listen but instead blindly trust in his own expectations and redundancy )
BTW: It looks like your using your RPi not as a backup target but to store maybe valuable data on it? If so ever thought about backing this data up?