Coyote Point Systems Equalizer GX Series, Administration Manual

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How the Load Balancer Determines if it Should Assume the Primary Role
Equalizer expects to see a heartbeat from a failover peer (all failover peers in Active/Active
Failover configuration [See
Configuring Active/Active Failover Between Two Systems ]).within a
"heartbeat interval" (time in seconds) on every subnet where a heartbeat flag is configured. When
a "Failed Probe Count" value is reached – that is, when that number of heartbeat probe intervals
has elapsed without receiving a heartbeat from a peer -the backup unit will attempt to assume
primary role.
Equalizer will:
1. Check to see if any of the cluster or failover IP addresses defined in its configuration are
already on the network -using ICMP requests/replies.
2. Perform checks on its locally defined networks and determine the number of subnets on
which it has connectivity. It compares this information to the connectivity information in the
last heartbeat received from the peer that reached the "Failed Probe Count" value.
a. If the Global "Failed Probe Count" on the failover configuration = 0, then the
"Failed Probe Count" configured on the subnet will be used to determine when
failover occurs.
b. If the Global "Failed Probe Count" is reached BEFORE the "Failed Probe Count"
configured on the subnet, then failover will occur.
c. If the "Failed Probe Count" configured on the subnet is reached BEFORE the
Global "Failed Probe Count" a failover will occur.
3. If the load balancer determines that no other systems own any of its cluster or failover IP
addresses AND it has better connectivity than the peer, it becomes "Primary" otherwise, it
will remain a "Backup".
Heartbeating MUST be established on an interface before failover can occur. If failover is
configured between two peers, and the cable is removed from the primary peer, the backup
will assume the role as the new primary. If the cable is removed from the "new" primary
BEFORE heartbeating has been reestablished with the previous primary, this peer WILL NOT
failover since heartbeating was never reestablished.
Copyright © 2014 Coyote Point Systems, A Subsidiary of Fortinet, Inc.
All Rights Reserved. 533
Equalizer Administration Guide