Number of times that the cluster member broadcasts extra address resolution protocol (ARP) packets when it takes on the primary role. (Even though a new NIC has not actually been connected to the network, the member does this to notify the network that a new physical port has become associated with the IP address and virtual MAC of the HA cluster.) This is sometimes called “using gratuitous ARP packets to train the network,” and can occur when the primary node is starting up, or during a failover. Also configure ARP Packet Interval.

Normally, you do not need to change this setting. Exceptions include:

Increase the number of times the primary node sends gratuitous ARP packets if an active-passive cluster takes a long time to fail over or to train the network. Sending more gratuitous ARP packets may help the failover to happen faster.

Decrease the number of times the primary node sends gratuitous ARP packets if the cluster has a large number of VLAN interfaces and virtual domains. Because gratuitous ARP packets are broadcast, sending them might generate a large amount of network traffic. As long as the active-passive cluster fails over successfully, you can reduce the number of times gratuitous ARP packets are sent to reduce the amount of traffic produced by a failover.

The valid range is 1 to 60. The default is 5.

Number of seconds to wait between each broadcast of ARP packets.

Normally, you do not need to change this setting. Exceptions include:

Decrease the interval if an active-passive cluster takes a long time to fail over or to train the network. Sending ARP packets more frequently may help the failover to happen faster.

Increase the interval if the cluster has a large number of VLAN interfaces and virtual domains. Because gratuitous ARP packets are broadcast, sending them might generate a large amount of network traffic. As long as the active-passive cluster fails over successfully, you can increase the interval between when gratuitous ARP packets are sent to reduce the rate of traffic produced by a failover.

The valid range is from 1 to 20. The default is 6 seconds.

Set the network interface to be used for data synchronization among cluster nodes. You can configure up to two data ports. If one data port fails, its traffic fails over to the next data port. If all data ports fail, data synchronization traffic fails over to the heartbeat port. If you do not configure a data port, the heartbeat port is used for synchronization.

Use the same port numbers for all cluster members. For example, if you select port3 on the primary node, select port3 as the data port interface on the other member nodes.

Number that identifies the HA cluster.

Nodes with the same group ID join the cluster.

If you have more than one HA cluster on the same network, each cluster must have a different group ID.

The group ID is used in the virtual MAC address that is sent in broadcast ARP messages.

The valid range is 0 to 31. The default value is 0.

Name to identify the HA cluster if you have more than one.

This setting is optional, and does not affect HA function.

The maximum length is 63 characters.

Number of 100-millisecond intervals at which heartbeat packets are sent. This is also the interval at which a node expects to receive heartbeat packets.

This part of the configuration is pushed from the primary node to member nodes.

The valid range is 1 to 20 (that is, between 100 and 2,000 milliseconds).

Note: Although this setting is pushed from the primary node to member nodes, you should initially configure all nodes with the same Detection Interval to prevent inadvertent failover from occurring before the initial synchronization.

Number of times a node retries the heartbeat and waits to receive HA heartbeat packets from the other nodes before concluding the other node is down.

This part of the configuration is pushed from the primary node to member nodes.

Normally, you do not need to change this setting. Exceptions include:

Increase the failure detection threshold if a failure is detected when none has actually occurred. For example, in an active-passive deployment, if the primary node is very busy during peak traffic times, it might not respond to heartbeat packets in time, and a standby node might assume that the primary node has failed.

Decrease the failure detection threshold or detection interval if administrators and HTTP clients have to wait too long before being able to connect through the primary node, resulting in noticeable down time.

The valid range is from 1 to 60.

Note: Although this setting is pushed from the primary node to member nodes, you should initially configure all nodes with the same HB Lost Threshold to prevent inadvertent failover from occurring before the initial synchronization.

Set the network interface to be used for heartbeat packets. You can configure one or two heartbeat ports.

Use the same port number for all cluster members. For example, if you select port3 on the primary node, select port3 as the heartbeat interface on the other member nodes.

Note: If a switch is used to connect the heartbeat interfaces, the heartbeat interfaces must be reachable by Layer 2 multicast.

Enable to synchronize Layer 7 session data used for persistence to backend servers.

When enabled, the source IP address table for sessions is synchronized to support sessions that use the source IP address persistence method.

When not enabled, a node that receives traffic because of load balancing or failover would not know that a session had been created already, so it will be treated as a new session.

Enable to synchronize Layer 4 session data used for persistence to backend servers.

When enabled, the source IP address table for sessions is synchronized to support sessions that use the source IP address persistence method.

When not enabled, a node that receives traffic because of load balancing or failover would not know that a session had been created already, so it will be treated as a new session.

Enable to synchronize Layer 4 connection state data.

When enabled, the TCP session table is synchronized. If subsequent traffic for the connection is distributed through a different cluster node because of failover, the TCP sessions can resume without interruption.

When not enabled, a node that receives traffic because of failover would not know that a session had been created already, and the client will be required to re-initialize the connection.

A number that uniquely identifies the member within the cluster. The valid range is 0-7. In an active-active deployment, this number is used in the virtual MAC address that is sent in ARP responses. In an active-passive deployment, this number is not used.

• active-active
• active-passive
• standalone

One or more network interfaces that correlate with a physical link. These ports will be monitored for link failure.

Port monitoring (also called interface monitoring) monitors physical network ports to verify that they are functioning properly and linked to their networks. You can monitor physical interfaces and 802.3ad aggregated interfaces.

Note: To prevent an unintentional failover, do not configure port monitoring until you configure HA on all appliances and have plugged in the cables to link the physical network ports that will be monitored.

Specify the node IDs for the nodes in the cluster. An active-active cluster can have up to eight members.

Enable to make Device Priority a more important factor than uptime when selecting the primary node.

Number indicating priority of the member node when electing the cluster primary node.

This setting is optional. The smaller the number, the higher the priority. The valid range is 0 to 9. The default is 5.

Note: By default, unless you enable Override, uptime is more important than this setting.

If failover occurs due to a remote IP monitor test, and this node's role changes (to master or slave), it cannot change again until the holdtime elapses. Holdtime can be used to prevent looping.The default holdtime is 120 seconds. The valid range is 60-86400.