This script creates a BtrFS-SR and SMB share with bcache on the Proxmox host.
curl -O https://raw.githubusercontent.com/Momi-V/ProxShare/main/createSHR.bash
cat createSHR.bash #look at the things you download
bash createSHR.bash
The script asks for the smb password to use, but is currently hardcoded to format nvme0n1 and all sd* drives.
Set bcache sequential cutoff to different value (4M) temporarily
echo $(( 1024 * 4096 )) | tee /sys/block/bcache*/bcache/sequential_cutoff
cat /sys/block/bcache*/bcache/sequential_cutoff