trurl

Not clear what you mean by "disabling" in the context of a drive that is not part of the parity array.

A new parity check does not reference anything that happened on previous checks. Why would it?

Just to pick my own nit here. It is possible to write to the rebuilding disk. If rebuild had not already progressed to that block of the physical disk, then parity update results in emulated write. If rebuild had already written the block, then the physical disk is written with the new data and parity updated as usual.

Sorry, my bad. It is disk3 that has no shares. So take everything I said before but apply it to disk3. You can see for yourself that disk3 has no shares by clicking on the File Explorer shortcut to disk3 in Main - Array Devices

Looks like disk2 has been formatted and doesn't contain any shares. Your Mediathek share has files on all other disks and isn't configured to exclude any disks, so I suspect the files that are missing were on disk2. Don't see anything in syslog or previous about formatting so must have happened before that. Was disk2 unmountable at some point so you allowed Unraid to format it so it would mount?

Contents of disabled disk is already emulated whether or not it is assigned and contents of physical disk aren't used for reading or writing until rebuild completes. So it's possible emulated disk has some data that the physical disk does not since the disabled disk isn't used for any writes that happened after, they are emulated instead. The emulated writes can be recovered by rebuilding so that is the standard approach since the physical disk may not have everything. Safest approach is to rebuild to a spare disk as you plan to do, so the original disk isn't changed. That way if there is some problem with the rebuild, the original is a "backup".

That is not the Diagnostics ZIP, just syslog. The word Diagnostics in my post and your post and wherever it appears in the forum is automatically a link to the documentation explaining how to get Diagnostics. It is a single ZIP file. Be sure to Attach Diagnostics ZIP to your NEXT post in this thread. Make sure it is the ZIP file, not the unzipped folders.

You don't want to use FAT32 for an assigned disk.

Attach Diagnostics ZIP to your NEXT post in this thread.

No reason to think rebuilding parity ( which I assume is what you mean by "rebuild the array" ) would result in anything other than what a correcting parity check does.

Attach Diagnostics ZIP to your NEXT post in this thread.

If the failed drive was empty you can New Config with the smaller drive in place of the failed drive, let parity rebuild, and format the new drive during or after parity rebuild. Or New Config/Rebuild Parity with nothing in place of the failed drive since 250G is perhaps not big enough to bother with.

Click on the container icon and select log from the pop-up

@Ellol Please describe your problem.

USB not recommended for assigned disks. There are external enclosures with SAS connections though. Sounds like a new case with better cooling and more bays could be a good place to start upgrades.