2.1.4 Configuring with two IBM LinuxONE servers Path length considerations LPAR considerations This scenario extends the previous single configuration with the possibility of greater  availability and disaster recovery. This two-server configuration can range from a simple cold  standby to an active/active configuration. As a foundation, duplicate the components and  locate them (at a minimum) in two different computing rooms, or (for maximum protection) at  two different site locations. For clarity and use purposes, name one site as  primary  and the  other site as  DR . This naming purpose is especially important to the disk storage subsystem  for your failover procedures. This naming can be diminished to each stage. You can verify  usability by reverting the primary and DR sites during a testing stage. With the two-server  configuration, you are able to spread all the I/Os over all the disk storage boxes and use the  cache of each box.  Calculate the length of the path between the IBM LinuxONE server and the storage  subsystem and between the two storage subsystems. The length influences the round-trip  time. Round-trip time is the amount of time between when a request is sent out and the  corresponding answer is received. This includes the following events: Ensure that the LPARS are spread across the machines, run more than one instance of each  service and distribute them over the defined LPARs. This two-server configuration with these  basics provides redundancy for both planned and unplanned outages in hardware and  software. Figure 2-2 on page 20 shows a two-site configuration. The shorter the round-trip time, the faster the process. GLYPH<SM590000> The signal travels on the wire to the receiver GLYPH<SM590000> The receiver gets the request, processes it and sends an answer GLYPH<SM590000> The answer travels on the wire back to the requester Figure 2-2 Two site configuration with full redundancy. In addition to a two-machine scenario, a configuration with three or more IBM LinuxONE  servers enables some quorum (automated decision making) in your environment. As in the  2.1.5 Configuring with three or more IBM LinuxONE servers 20  Temenos on IBM LinuxONE Best Practices Guide