Coyote Point Systems Equalizer GX Series, Administration Manual

Page: 577 / 866

Configuring Active/Active Failover
Active/Active (A/A) failover allows clusters to be active on both Peers that are configured into
failover. For the same failure situations that cause a Peer to take over all the cluster and floating
IP addresses in an Active/Passive failover configuration, Active/Active failover operates the same
way - that is that the healthy Peer will take over all of the cluster and failover IPs.
An Active/Active failover configuration consists of two peers. Equalizer’s clusters are instantiated
on both peers and organized into “Failover Groups”. If the one peer’s connectivity for the failover
group’s resources is judged to be “healthier” than the peer on which the group is running, then the
group “fails over” to the other peer.
It should be noted that if and when the "sick" Peer is healed, there is no automatic migration of
the clusters back to it. You can, however, invoke a "rebalance" command to make this happen.
Failover Groups
Active/Active failover introduces the concept of "Failover Groups". A Failover Group consists of all
the smallest set of resources that may be moved between Peers and can consist of one or more
clusters, servers, and failover IPs.
Failover Groups are dynamically determined by the configuration and cannot be specified by the
user.
In the simplest case, there is a maximum of 1 Failover group per subnet. However, based on the
cluster/match rule/server pool/server configuration, a Failover Group may contain more than one
subnet. Basically, the algorithm is that:
l
a cluster subnet and, for non-Spoof match rules, all associated server subnets must all be in
the same Failover Group. This means that all clusters and failover IPs on any of these sub-
nets are in the same Failover Group.
l
if spoof is set for all the cluster match rules, then the server subnets are not factored into
the Failover group.
This means that as clusters and servers are added or deleted, the Failover group configuration
may change.
Copyright © 2014 Coyote Point Systems, A Subsidiary of Fortinet, Inc.
All Rights Reserved. 577
Equalizer Administration Guide