I woke up to a concerning situation today, hopefully it's an issue with my understanding of how BI handles data and a tweak of my settings can prevent from happening again.

I have two 12tb mechanical disks, one internal (D), and the other in an external drivebay enclosure (E).

Disk D is my NEW folder, and should move the oldest footage to Stored (limit size: 10,000gb, move to folder Stored selected).

Disk E is my STORED (limit size 10,000gb, Delete selected).

This morning I noticed that there was no video available since around 1am. The external drive enclosure had powered down and required a reset. The internal disk (NEW - D:) was overfilled with only a few bytes of data available, there should be almost 2tb free.

How do I prevent this from happening again? The priority should always be recording new footage. If the stored drive is down for any reason, that should be a secondary objective (backing up the oldest footage coming out of the NEW folder should be secondary to recording NEW footage)

Hmm thats an interesting one. Your config seems right but perhaps there needs to be a logic enhancement within BI (not your ability currently I don't believe). It sounds like there is a potential issue IF a subsequent drive is unavailable. This one might be an email to support asking for advice and if nothing else, an addition to the feature request list. Something like a check box to "overwrite/delete if 'Move to folder' is unsuccessful"

The issue here seems to be the external drive powering down - If there is no method to adjust those drive settings, is there any way you can remove that second drive from its enclosure and fit it within the BI5 pc ?

The OP's post also answers a recent query from another member on what would happen with BI5 if his NAS "Storage" folder was unavailable. I suspected it wouldn't end well

TimG wrote: ↑Sat Oct 10, 2020 2:49 pmThe OP's post also answers a recent query from another member on what would happen with BI5 if his NAS "Storage" folder was unavailable. I suspected it wouldn't end well

My NAS occasionally locks up or goes incommunicado and BI just stacks up the videos to be sent to it until connectivity returns.

I think this only works because I have a large amount of space reserved for the /New storage, significantly more than it would normally use as it shuffles the older videos up to the NAS.

Yes that will happen, You have to make sure all the drives "Space" connected to Blueiris are always available. If you have multiple folders you want video files moved between and one folder or drive is removed then the video files from the upper folders have nowhere to go and will start filling up the first folder/drive until it's completely filled.
USB drive for the camera files is not a good idea. NAS is better than USB drive but try connecting the NAS directly to the blueiris server on a separate network as more NAS's have two nics that why there will be less to go wrong on the network side of things.
Best setup is to have the HDD in the Blueiris server.