Fortinet FortiGate FortiGate-5001 Administration Manual page 94

HA
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Group ID
The group ID range is from 0 to 63. All cluster units must have the same group ID.
When the FortiGate units are switched to HA mode, all of the interfaces of all of the
cluster units acquire the same virtual MAC address. This virtual MAC address is set
according to the group ID.
Table 3: HA group ID and MAC address
Group ID MAC Address
0
00-09-0f-06-ff-00
1
00-09-0f-06-ff-01
2
00-09-0f-06-ff-02
3
00-09-0f-06-ff-03
...
...
63
00-09-0f-06-ff-3f
If you have more than one HA cluster on the same network, each cluster should have
a different group ID. If two clusters on the same network have the same group ID, the
duplicate MAC addresses can cause addressing conflicts on the network.
Unit Priority
Optionally set the unit priority of the cluster unit. Each cluster unit can have a different
unit priority. The unit priority is not synchronized among cluster members. Each
cluster unit can have a different unit priority. During HA negotiation, the unit with the
highest unit priority becomes the primary unit. The unit priority range is 0 to 255. The
default unit priority is 128.
You can use the unit priority to control the order in which cluster units become the
primary unit when a cluster unit fails. For example, if you have three FortiGate units in
a cluster you can set the unit priorities as shown in
be the primary unit because it has the highest priority. If cluster unit A fails, cluster
unit B becomes the primary unit because cluster unit B has a higher unit priority than
cluster unit C.
Table 4: Example unit priorities for a cluster of three cluster units
Cluster unit
A
B
C
In a functioning cluster, if you change the unit priority of the current primary unit to a
lower priority, when the cluster renegotiates a different cluster unit becomes the
primary unit.
01-28008-0013-20050204
Table 3 lists the virtual MAC address set for each group ID.
Unit priority
200
100
50
System Config
Table 4. Cluster unit A will always
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