JorgeB

If you assign the new parity drive can you not start the array? If yes post a screenshot of main after doing that.

All except the first one have a downgraded link:
 
LnkSta: Speed 5GT/s, Width x1 (downgraded)  
One of those has 7 devices, so 400/7=57MB/s, around what you are seeing.
 
Issue should also be visible with the diskspeed docker, but if you run the controller test, where all devices on the controller are benchmarked together.

And did you leave it as parity2 or assigned it to parity1? They are not interchangeable.
 
 

Is turbo write enabled on the destination server? You can also mount the share(s) from one of the servers with UD and use rsync instead.
 
 

Take a look here first:
https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=972660
 

Disk dropped offline, it's on a Marvell controller, those are known to sometimes drop devices with no reason, suggest replacing it if possible.

Emulated disk7 is mounting, you can now reassign the disk to rebuild.

Since it's still mounted read-only suggest to backup what you can, then re-format.

It means any data currently on that disk (if it's not empty) will be overwritten during the rebuild.
 
This usually happens with Firefox if you hit "Resend" on a popup, don't use Firefox with the GUI or never hit resend.

Sep 13 12:34:14 GenX-Nas emhttpd: shcmd (214): umount /var/lib/docker Sep 13 12:34:14 GenX-Nas root: umount: /var/lib/docker: target is busy  
Docker is failing to unmount, try updating to v6.12.4 since it fixes a known issue with that.

Likely due to hardware changes you are now passing trhough the HBA toi the BlueIRIS VM:
 
0a:00.0 RAID bus controller [0104]: Broadcom / LSI SAS2008 PCI-Express Fusion-MPT SAS-2 [Falcon] [1000:0072] (rev 03)
    Subsystem: Fujitsu Technology Solutions HBA Ctrl SAS 6G 0/1 [D2607] [1734:1177]
 
Edit the XML and remove/correct this:
 
<hostdev mode='subsystem' type='pci' managed='yes'> <driver name='vfio'/> <source> <address domain='0x0000' bus='0x0a' slot='0x00' function='0x0'/> </source> <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/> </hostdev> <hostdev mode='subsystem' type='pci' managed='yes'> <driver name='vfio'/> <source> <address domain='0x0000' bus='0x0a' slot='0x00' function='0x1'/> </source> <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/> </hostdev>  
Device 0a:00.1 doesn't currently exist, but still should be corrected.

Btrfs is gone from this device, looks like it was wiped or removed from the pool.
 
Try just the SSD assigned top the pool and post new diags after array start

As you can see the GUI is correct 776GiB=833GB, you'll need to go inside the folders and see what using the space, if you posted the complete results there are no snapshots taking space.

Take a look here:
https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=972660
 

Try removing the device again, stop array, unassign device you want to remove, start array, post new diags.

That's strange, disks don't usually change capacity on their own, but since it did you'll need to rebuild, check that the emulated disk is mounting first.

OK, now create a temp folder inside /mnt/plot_share, cd into it and type:
 
dd if=/dev/urandom bs=1024 count=1050000 | split -a 6 -b 2k - file.  
This will create many small files in that folder to force allocate some metadata chunks, once complete start copying data normally again, when the fs is close to full remove that temp folder.

The screenshot confirms the OS is already registered, Connect can take some time to show the correct key status, try rebooting, but like mentioned it's already registered, it won't stop working.

There's something writing to the array, stop that and speed should improve by a lot.

Disk/SSD

Sep  8 12:56:15 unhump root: Creating new image file: '/mnt/cache/system/docker/docker.img' size: 20G  
A new docker image was created, suggesting one didn't exist before, share is configured to cache=yes, meaning the image would be move to the array, but only if it didn't already exist and the docker service was stopped, do you have any custom scrips running on array stop?

A vdisk on HDDs is always going to be slow, a couple of things that may help a little:
 
-create a small disk for the OS on SSD storage, and set the pool as a second volume
-if usins raidz try mirrors if possible
-use a zvol instead
 

Unassign cache, start array, stop array, reassign cache, start array, current pool should be imported, if it's not post diags.

Start here:
https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=819173
 

If the log tree is the only problem this may help:
 
btrfs rescue zero-log /dev/nvme0n1p1  
Then re-start the array and post new diags.