Active Sync Between SAN clinets

Environment: We have Dell 3620f Storage of 60TB. It has connected the Storage with two machines with HBA cards, running Ubuntu 16.04.
Problem: Disks are visible and are mounted on both servers. But issue is that if one server writes some data, Update is not visible on the other servers. We want the disks to refresh automatically. We should not remount the disks on other servers as sometimes some files are in use from the disks.