Patent ID: 8780718

Claim:
A method for maintaining connection persistence by a backup virtual server, the method comprising: (a) receiving, by a virtual server configured on an intermediary device deployed between a client and a server, a request via a first connection established between the client and the server, the virtual server identified as a primary virtual server for the first connection, the virtual server having a backup virtual server, the virtual server being configurable to select between a first configuration that identifies that the virtual server does not preempt the backup virtual server from servicing connections currently serviced by the backup virtual server and a second configuration that identifies that the virtual server preempts the backup virtual server from servicing connections currently serviced by the backup virtual server; (b) forwarding, by the intermediary device, the request to the backup virtual server in response to identifying that the virtual server is unavailable; (c) identifying, by the intermediary device, that the virtual server is available; (d) establishing, by the virtual server, a second connection responsive to receiving a connection request; (e) receiving, by the intermediary device, a second request via the first connection; (f) determining, by the intermediary device, which of the first configuration or the second configuration has been selected for the virtual server's configuration, wherein selection of the first configuration for the virtual server's configuration causes the second request to be forwarded to the backup virtual server instead of the virtual server and wherein selection of the second configuration for the virtual server's configuration causes the second request to be forwarded to the virtual server instead of the backup virtual server; and (g) responsive to determining that the second configuration has been selected for the virtual server's configuration, preempting, by the intermediary device, the second request from being forwarded to the backup virtual server and forwarding, by the intermediary device, the second request to the virtual server instead of the backup virtual server.