JonathanM

Have you visited http://stretchoid.com/ ? They lay it out pretty clearly. I'm definitely not advocating blindly filling out their form, but maybe after some due diligence you could choose to interact with them or just ignore it.

https://xkcd.com/936/

I don't understand. Deleting the offending file should allow Unraid to work as designed. Does it not?

When an array disk read fails, Unraid immediately spins up all drives, calculates what the read should have returned, and attempts to write that value back to the disk with the failed read. So, any server running Unraid with spin down enabled must be capable of handling the sudden "all hands on deck" spin up.

Given the totality of your situation, I think it might be wise to take this opportunity to overhaul things completely. 4.7 uses ReiserFS exclusively, which is no longer recommended and performs very poorly with drives larger than 2TB. Please list all the components in your current system, motherboard, cpu, memory, power supply, HBA's, hard drives, etc. Also, how much storage is currently occupied? My initial thought is to back everything up to an external drive, and start over with a new version of unraid and whatever else is needed.

I'm not sure 4.7 supported larger than 2.2TB.

Because microsoft doesn't allow it.

Understand. We are trying to tell you booting from an SD card reader is not supported. You must use a USB flash drive.

That's normal when your Downloads share has a folder on the cache drive.

Delete BTRS.key from the config folder of the flash drive and try again.

Try nomachine, it works well for me.

Have you watched Spaceinvader One's content on youtube?

That statement does not compute. Parity is realtime, a check just verifies that all drives can be read accurately and the realtime parity has stayed in sync. If everything is working properly you should be able to replace the drive at any time and not lose anything.

You can't have a data drive larger than either parity drive.

A single copy of data is not backup, regardless of RAID level, Unraid parity, etc. RAID or Unraid only protects from disk failure, there are MANY more ways to lose data. Accidental or malicious deletion or corruption, user error... You must have a second copy of any data that you value.

Depends on the specific combination of hardware. There is a reason why S3 sleep isn't natively supported by Unraid, you are certainly welcome to try the 3rd party plugin to enable it, but there is no guarantee it will work properly.

Removing a drive from the array is what makes this different. If you just replaced the failed drive there wouldn't be an issue. If you were replacing a drive by rebuilding on a new drive, yes, that's what would happen. If you are rebuilding parity from scratch because you totally removed a slot assignment instead of rebuilding to a drive, then no, parity isn't valid until it completes. Replacing and rebuilding is totally different from removing a drive from the parity array.

Depends. There are some definite advantages to running a single drive with XFS format, and very few downsides. Running more than one drive in a cache pool requires BTRFS, which has some quirks. Either way you will have items that for performance reasons will stay on the pool long term, you need to have a backup strategy for those. How to best accomplish that depends on the specific type of thing, VM virtual disks, container persistent data, or just files that you want to have the highest possible speeds. Do you have enough space elsewhere to keep a copy of the data? Drives assigned to Unraid must be partitioned and formatted, you can't directly migrate disks full of data.

Parity doesn't restore files, it rebuilds the entire filesystem as it was.

Does the board have a piezo speaker, or just header pins for a speaker? Since you didn't mention beeping on startup, I'm guessing no speaker on board, so hooking up a speaker to see if the system is trying to tell you something may help. To start diagnosing a problem system I generally boot without RAM or any cards, just PSU, CPU, speaker. That should generate a beep code indicating no RAM, then I add the RAM back and see if the beep code changes.

What exactly are you expecting to see? There is no requirement for the cache to be SSD.

Tools, new config, assign drives how you want, rebuild parity.

Motivation is often just a few clicks away. 😎 (hint, see the last line of @olehj's signature block)

See if the NUT plugin changes things?

Do you have a windows pc you could temporarily connect to the USB and see if the status is correct there?