Resize SCSI LUN

/!\ Apply theses commands on each node of proxmox server /!\ My physical disk is /dev/sdb, please adapt for your case /!\ Remove VM or stop it before resize from Synology

Check the initial disk size

lsblk

Resize the LUN in SCSI manager from Synology DSM

Rescan the volumes and check again the right size of physical disk

iscsiadm --mode session --rescan
lsblk

Resize the physical volume

pvresize /dev/sdb

Enjoy !