A method of retransmitting a multicast message through a unicast channel in a virtual distributed storage system comprising a cluster of nodes that includes a master node and a set of agent nodes is provided. Each node maintains a copy of a directory of the virtual distributed storage system. The master node multicasts messages to the agent node through a multicast channel to update the directory. The method determines that a particular message to update the directory exceeds a maximum size limit for transmit to the agent nodes through the multicast channel. The method multicasts a retransmission trigger message from the master node to each agent node. The method receives a retransmission request message at the master node from each of the agent nodes through a unicast channel. The method sends the particular message to update the directory from the master node to each agent node through the unicast channel.