itimpi

It could be the Cache Dirs plugin which would keep issuing 'find' commands to try and keep directory entries in RAM.    It is a good idea to configure that plugin to only scan folders that need it as it does not work very well if there are too many files/folders in the ones it is scanning.

That shows that the Connect plugin is the culprit.    The most recent update to that plugin fixes the excessive logging issue, but you will still need to reboot the server to clear the log space used.

I think the problem is all the disks are now showing:
Formatted with type 2 protection I do not know if this can be removed and keep the data on the drives.

1.  Yes
2. You can give the licence files different names to help you tell them apart.   When transferring licences you put the licence file for the one you want to transfer into the ‘config’ folder on the new USB drive so it knows which one is being transferred.

You will need to contact support to resolve this.
 
Have you already used the 1 automated transfer allowed per year?  When that is exceeded you always need to go via support.

You will need to run without -n or nothing will be done.    If you get prompted for it then add -L.

A rebuild does not clear an 'unmountable' status as a rebuild gives you exactly what you can see before the rebuild.   The process for handling unmountable disks is covered here in the online documentation accessible via the Manual link at the bottom of the Unraid GUI.  In addition every forum page has a DOCS link at the top and a Documentation link at the bottom.   The Unraid OS->Manual section covers most aspects of the current Unraid release.

If you go the New Config route you can remove them all at once as after going this route you will be rebuilding parity to get your array back into a protected state.  You are unprotected until that finishes.  
 
An alternative process in the first place would have been to use New Config to both remove the old drives and add the new drives at the same time before copying/moving any files and then rebuild parity based on the new set.  You could then have mounted the old drives one at a time via the Unassigned Devices plugin to copy their contents back to the array.  This would have been the fastest approach although you would then not be protected against one of the old drives failing before you copied their data back to the array.
 
If you want to remain protected all the time then you need to remove them one at a time.
 

You need to reinstall the binaries for your docker containers (with previous settings intact) via Apps->Previous Apps->Docker.

It is a requirement of Unraid that each drive has a unique ID (typically serial number).   It looks as if the USB3 chassis you are using does not pass through the serial numbers and has given both drives the same ID.   The only fix to this is a different USB3 chassis that DOES have unique ID's for each drive.

Yes.   You only want the driver if you intend to use the GPU in docker containers.   If passing it through to a VM you do not want the driver.

You seem to have a network problem limiting your speeds.  It is as if you are only connecting at about 100 Mbps.
 
Have you tried alternative LAN cables and/or ports on the router?   If not all ports on a LAN connection are connecting the speed will silently degrade to 100Mbps as that connection needs less active connections in the cable than is required for 1000 Mbps.

Put the extra disk in a pool;  Creat a Downloads share which has the pool set as primary storage and no secondary storage;   Set the media share to have the pool as primary storage; the array as secondary storage and mover direction to be pool->array.

You seem to be getting continual resets on disk3 which probably explains the slow speed.   You might want to check the power and/or sata cabling to the drive is well seated.  I assume the PSU is up to handling the extra drive?
 
BTW:  You probably need to disable spindown to get the Extended SMART test to complete.   If the drive cannot pass that it will need replacing.

I would think the most likely things to cause a reboot would be thermal (e.g. CPU overheating), or PSU issues.

The disk assignments have always been held in the super.dat file in the backup.   This is a binary file and thus not human readable.   Not sure when/how the disk_assignments .txt file gets created.

The parity check checks all of the parity disk as being correct.  Since your parity drive is larger than your biggest data drive it is checking that the remaining part of the parity disk is all zeroes.

Do you have “turbo Write” mode enabled?   If not then I expect the initial burst of speed happens while data is being cached to RAM and then the 30-50 MBps speed that continue is not atypical when writing to a parity protected array.  This section of the online documentation accessible via the ‘Manual’ link at the bottom of the GUI or the DOCS link at the top of each forum page describes what is going on.   The Unraid OS->Manual section in particular covers most features of the current Unraid release.

There should be only 1 key file (presumably the Plus key as the last one that was valid).

You need to have two different shares if you want them to be treated differently by mover

Not sure what you mean?  Nginx is built into Unraid as it runs the webGUI.

At any point in time the parity check speed will be determined primarily  by the slowest drive currently involved.  The first 4TB would be no faster.    Once you get past the size of the data drives I would expect it to speed up dramatically

I think that the spindown on a SSD often just puts it into a lower power state.

If you want to continue using macvlan make sure that bridging is disabled on eth0 (as mentioned in Release notes).

The color coding just looks for certain strings in the log entries.    I am guessing that ‘checksum’ and ‘error’ are strings being looked for.    The lines look like perfectly normal information messages.
 
i notice that you are using macvlan networking for docker.   If you experience instability you might want to consider switching to ipvlan as mentioned in the Release Notes.