Product Documentation

Active-passive site deployment

An active-passive site consists of an active and a passive data center. This deployment type is ideal for disaster recovery.

In this type of deployment, some of the sites (remote sites) are reserved only for disaster recovery. These sites do not participate in any decision making until all the active sites are DOWN. A passive site does not become operational unless a disaster event triggers a failover.

Once you have configured the primary data center, replicate the configuration for the backup data center and designate it as the passive GSLB site by designating a GSLB virtual server at that site as the backup virtual server.

An active-passive deployment can include a maximum of 32 GSLB sites, because MEP cannot synchronize more than 32 sites.

For an active-passive deployment, you can configure the following GSLB methods.

  • Round Robin
  • Least Connections
  • Least Response Time
  • Least Bandwidth
  • Least Packets
  • Source IP Hash
  • Custom Load
  • Round Trip Time (RTT)
  • Static Proximity

Note:

  • If MEP is disabled, the following algorithm methods default to Round Robin.
    • RTT
    • Least Connections
    • Least Bandwidth
    • Least Packets
    • Least Response Time
  • In the static proximity GLSB method, the appliance sends the request to the IP address of the site that best matches the proximity criteria.
  • In the Round Trip Time method, the dynamic round trip time (RTT) values are to select the IP address of the best performing site. RTT is a measure of the delay in the network between the client’s local DNS server and a data resource.

GSLB active-passive datacenter topology

In the diagram, Site 1 is an active site and Site 2 is a passive site, which has the same configuration as that of Site 1.

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If Site 1 goes DOWN, Site 2 becomes operational.

When the client sends a DNS request, the request can land in any of the sites.  However, the services are selected only from the active site (Site1) as long as it is UP.

Services from the passive site (Site 2) are selected only if the active site (Site 1) is DOWN.

Active-passive site deployment