Se eu estou lendo a sua pergunta corretamente, usar timeout server
para 1 segundo (1000 ms) e usar option redispatch
deve dar o efeito desejado.
option redispatch
no option redispatch
Enable or disable session redistribution in case of connection failure In HTTP mode, if a server designated by a cookie is down, clients may definitely stick to it because they cannot flush the cookie, so they will not be able to access the service anymore.Specifying "option redispatch" will allow the proxy to break their persistence and redistribute them to a working server.
It also allows to retry last connection to another server in case of multiple connection failures. Of course, it requires having "retries" set to a nonzero value.
This form is the preferred form, which replaces both the "redispatch" and "redisp" keywords.
If this option has been enabled in a "defaults" section, it can be disabled in a specific instance by prepending the "no" keyword before it.