1. A method comprising: determining by a first network device that the first network device is ready to apply a volume hierarchy; sending by the first network device a notification message to at least one other network device, wherein the notification message indicates that the first network device is ready to apply the volume hierarchy; receiving a command at the first network device to apply the volume hierarchy, wherein the command indicates that one or more other network devices are also ready to apply the volume hierarchy; and applying the volume hierarchy at the first network device so that the first network device processes input/outputs (IOs) using the volume hierarchy.