for the container check Options -> Features if NFS is enabled (needs to be a privileged container).
The other possiblity is to mount the NFS share on the Proxmox server and use a bind mount  to mount it into the container.
A bit more information would be nice. Do you get past the BIOS and see the bootloader and kernel messages before this error appears?
Also, do not install Proxmox on an SD card! It will not last long because Proxmox VE is writing quite a bit on it like logs.
Check the IOMMU Groups column. Your problem sounds a lot like the one problematic GPU and your main network interface are in the same group. You can only pass through the whole group and not individual device of the same group.
Ceph geht erst an 3 nodes ja.
Welche VMs auf welchem Node laufen musst du abwiegen.
Du kannst den zweiten Node auch als fallback nutzen. Mit ZFS als Storage kannst du auch eine Replikation der VMs zwischen den Servern haben .
Mit einer dritten Maschine (gerne werden Raspberry Pis genommen)...
Well, for HA you need at least three nodes in the cluster. But the third node doesn't need to be a full Proxmox VE installation. You can add a so called QDevice to the cluster. Basically a service that needs to be installed on the Proxmox nodes and the counterpart on a third device. Check our...
If you pass through the device as described in the link of my previous comment the VM should be able to access it like it would be connected directly to the drive.
No mounting within Proxmox just passing through the drive to the VM. You then mount it in the VM.
Ah, The used column shows the full size if you did not enable thin provision. The whole size of the disk is reserved in that case. The actual usage is in the Refer column.
Without any experience with dedup myself there are two things that I see. First the DEDUP column which shows that there are...
Yes using a central storage server for the VMs is possible. Use either iSCSI or NFS to export the storage to the Proxmox servers.
Please check our documentation for more details.
Where did you read this? It sounds a bit weird to me.
The way to go with a central storage is to export the storage as either iSCSI or NFS. See our documentation for supported storage types.
If you do this use a separate physical network to connect to the storage to avoid problems. The storage...
With only one SSD for the new fast storage and regular backups to the HDDs you must know if you are okay if you lose all the data until the last backup if the SSD fails. Don't forget the time until you restore the backup and have the VM up and running again.
For the speedup: most likely yes but...
By default dedup is not enabled because it needs a lot of resources.
Have you enabled it on the ZFS storage?
Also look into enabling compression. This way depending on what your data looks like you can still get some nice space savings without the big cost in resources needed for it.
Please provide direct links to the document you followed so everybody can load it without searching around.
Also there seems to be a bit of information missing, especially how your Proxmox and VM (network) configuration is set up.
Since I don't have any experience with this exact setup I cannot guarantee that this will work. Because it is connected via SAS this guide can work for you. https://pve.proxmox.com/wiki/Physical_disk_to_kvm
The best is to build a test setup and see if it works for you.