grace Maintain a proxy operational for some time after a soft stop May be used in sections :

defaults frontend listen backend yes yes yes yes yes yes yes yes Arguments : is the time (by default in milliseconds) for which the instance will remain operational with the frontend sockets still listening when a soft-stop is received via the SIGUSR1 signal. This may be used to ensure that the services disappear in a certain order. This was designed so that frontends which are dedicated to monitoring by an external equipment fail immediately while other ones remain up for the time needed by the equipment to detect the failure.

Note that currently, there is very little benefit in using this parameter, and it may in fact complicate the soft-reconfiguration process more than simplify it.