The secondary SpectroSERVER maintains a TCP/IP connection to the primary SpectroSERVER. If that connection is severed due to the primary SpectroSERVER crashing or being shutdown the secondary will immediately be notified and become active.
The secondary SpectroSERVER is also sending a lightweight request once a minute to the primary. If the primary becomes hung and doesn’t respond within 3 minutes, or there is a network problem preventing the request from reaching the primary (or the response from coming back) the secondary will become active.
The 3 minute interval is configurable by setting the “vnm_message_timeout” (specified in milliseconds) in the .vnmrc file of the secondary. CA recommends that you do not change this setting unless there are problems or you are instructed to change this by CA Support.