Gragorg

There is a parity swap procedure. This will allow you to use your current parity to replace the bad data drive and use the 24TB as a new parity.

Since you ran the repair with "-n" nothing was actually changed it just does a dry run to show you what it would do. You need to remove the -n to actually allow it to make the repairs. There is a great spaceinvaderone video on this if you want more information found here.

Apparently I just needed to set a proper path for ISOs. I'll leave this here incase it helps someone in the future.

I believe this is the post Jorgeb is talking about.

You can move the data off one of the data drives and shrink the array.  Once complete you reassign the empty data drive at parity 2.  On the bottom right corner of the GUI click on manual and look up "shrink array"

Your port forwards look correct but you only need to forward tcp only.   Plex is usually setup as HOST.  Most create a custom docker network for arrs and Nginx.  Nginx normally shares an ip with the server.
If you want to create a custom docker network just type the following in terminal
 
 
docker network create "name of network (without the quotes)"
 
This network name will then show on "Network Type" on docker templates.
 
 
 
 
 
Yes

You appear to have a cabling issue on ATA3 (ST2000DM008-2UB102).  Check/replace cables and try again.

1.  You will be limited to speed of the single array drive.  Of course ZFS pools will be faster than a standard array but you lose the flexibility to easily expand as needed.
2.  If you install Unraid Connect it will back up USB for you periodically.
3.  In my experience it take 2-3 seconds to spin up a drvie.  If a video is started it will only spin up the drive with the video.
4.  You would just leave the drive unassigned.  You would select the drive manually that you want to replace.  You don't really want this automated as it could fail due to power or connection problem.

I use cloudflare free account for all dns and would recommend it.  It has a ton of videos on youtube.  I was using SWAG but switched to Nginx Proxy Manager for simplicity.  I also bought domain at Godaddy and changed the nameservers to cloudflare.  If i add a docker I can add a CNAME on cloudflare and cert on NPM in 5 minutes.

If your disk is good and you are rebuilding on the exsisting disk
 
1. Stop the Array
2. unassign the disk with the x
3. Start the Array
4. Stop the Array
5. Re assign the same disk
6. Start the Array
 
The rebuild will start and rebuild on the disk

Post diagnostics.  Its very likely a bad cable/connection
 

Server RASPBERRYPI at IP 192.168.0.245

Only one copy of the files exist at on time.  They are either on the array or on the cache.

Did you try and put the USB stick in a windows machine to see if detects errors?  If it does let windows fix them.

Here is the information from the manual.

Once cabling is fixed and logs are clear
1. Stop the array
2. Unassign parity drive
3.  Start the Array
4. Stop the Array
5. Assign the parity drive back
6. Start the Array ( this will start parity reconstruct)

This is from the manual

Yes its not an issue.

The requirement for an array device is going to be removed in a future release.  The ZFS zpool has higher performance but drives do not spin down.  The array allows you mix and match hard drive sizes and expand one drive at a time when needed.  It also spins down unused drives to save power but performance is limited to the performance of a single drive as data is not striped.  If you lose one drive your data is covered in both cases (array and raidz).  If you lose two drives the raidz pool you would lose your data while the array would only lose the two failed disks and all remaining data would be intact.  You can add a second parity to the array to have a two disk fault tolerance. 

Possibly the router updated and restarted?  If you type //broxi into the web browser it should load your gui regardless of ip.

You shouldn't have to change swags container ports from 80 and 443.  Container ports are unique to the containers.  Domain forwarding in router is not required that is what SWAG does.  On your DDNS docker did you remove the email field?  If this allows Cloudflare DDNS to run you don't need DuckDNS to track your ip that is what Cloudflare DDNS does. Your containers don't really need any configuration since SWAG is just directing to their exsisting web gui.  Having said that I was a former SWAG user and found it to be not very user friendly to add new proxy entry.  I now prefer Nginx Proxy Manager as it is very simplified.  Also why did you have to change port 80 and 443 for unraid?  If your only looking to use only Nginx in Swag then NPM is far more simplified.  These are the videos that I used to accomplish reverse proxy using NPM if you want to go that route.
 
Buy Domain and connect it to cloudflare. Here is a great video
Follow DynDNS portion of this video at 9:20 skip the duckdns part.
I used this video for NPM

If your Extended Smart test is good and you want to clear the status you can hit the "Clear Stats" button at the bottom of the main tab.  If the counts increases it will show back up.

Hit the little "?" icon in the top right corner of the gui

Keep appdata and domains on the Cache.  it is so much faster and lower power consumption.  My Mx500 I use for my cache shows Power on hours as 6y 3m 14d.  I wouldn't really worry about SSD wear and tear.  If your worried about it you can mirror 2 in a cache pool.  Shares such as media and what not are stored on the array.

Follow this video from Spaceinvader one.