Proxmox Host /boot is  98% Full 
 
how the Disk is used? # df -T -h
look with "pveversion -v" and still keep the latest and the running kernel.
cd /boot
/boot# ls -lha
Seems you have a lot of kernels installed.
You can list those packages with:
# dpkg -l |grep pve-kernel
And you can remove them with:
# dpkg --remove <pgname>
    
            
            
            
                
how the Disk is used? # df -T -h
look with "pveversion -v" and still keep the latest and the running kernel.
cd /boot
/boot# ls -lha
Seems you have a lot of kernels installed.
You can list those packages with:
# dpkg -l |grep pve-kernel
And you can remove them with:
# dpkg --remove <pgname>