Hi,
Traffic is forwarded to the available server for new connections only.
but, If used persistence profile, It not come back Client connection when have persist and connection table.
Seçkin1983 said
'F5 do not send the all client traffic immediately instead will send new connections gradually'
--> options is 'Slow Ramp Time '
Slow Ramp Time
Specifies the duration during which the system sends less traffic to a newly-enabled pool member. The amount of traffic is based on the ratio of how long the pool member has been available compared to the slow ramp time, in seconds. Once the pool member has been online for a time greater than the slow ramp time, the pool member receives a full proportion of the incoming traffic. Slow ramp time is particularly useful for the least connections load balancing mode
Setting this to a nonzero value can cause unexpected Priority Group behavior, such as load balancing to a low-priority member even with enough high-priority servers.