After a distributed portgroup is removed, it is possible MSA would not be able to show the list of networks. The workaround is to restart MSA service (DRBC-7063)
Changes to per-network routing tables are not propagated to already deployed appliances. (DRBC-7586)
In case DRVA is configured with multiple network interfaces, and internal communication interface is not available from some hosts for some reason, there is a possibility of an internal deadlock in IOFilter daemon on affected hosts, resulting in various operation failures and subsequently CIM communication errors. The workaround is to kill the daemon on the hosts after communication with DRVA is restored. The fix will be available in version 4.2.2. (DRBC-7296, DRBC-7795, DRBC-7813)
In case DRVA cannot be reached from some host(s), and IOFilter issues many requests for getting a DRVA address to MSA, it is possible that IOFilter internal state would become corrupted. This results in inability to continue replication and inconsistent state of data in the object cloud. In some cases this could lead to failures taking a snapshot. There's no workaround, affected VMs must be re-protected. The fix will be available in version 4.2.2. (DRBC-7827)