A replicated VM becomes unresponsive or cannot serve network requests

During a vSphere Replication sync operation, the VM disk I/O blocks for the duration of the sync.

Problem

The vSphere Replication filter driver fails the SCSI UNMAP commands during a sync operation, if these commands override the transfer of the current replica disk to the target site.

You must allow vSphere Replication to accommodate the UNMAP commands.

Solution

1. Establish an SSH connection to the source ESXi Server.
2. Run the following command:
   esxcli system settings advanced set -o /HBR/DemandlogFailCollidingUnmap -i 0

   The command takes immediate effect and you don't need to perform a system reboot.