Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 323)

Brocade Virtual ADX Server Load Balancing Guide 307
53-1003247-01
Hot Standby HA configuration modes
6
When the entire synchronization process is completed, Brocade Virtual ADX-B calculates Brocade
Virtual ADX-A router-port plus server-port count.
• If the Brocade Virtual ADX-A count is greater than or equal to Brocade Virtual ADX-B, Brocade
Virtual ADX-A remains in the active state and Brocade Virtual ADX-B remains in the standby
state.
• If Brocade Virtual ADX-A has a lower count of the router port plus the server port, Brocade
Virtual ADX-B forces Brocade Virtual ADX-A to the standby state, and Brocade Virtual ADX-B
sets itself to the active state.
To avoid a loop, the standby Brocade Virtual ADX becomes a dumb device. It is completely isolated
and does not process any SLB traffic. However, while the standby Brocade Virtual ADX is idle, it
performs the following functions:
• Continuously listens to the active Brocade Virtual ADX for failover preparation and receives
session-sync messages from the active Brocade Virtual ADX. The moment a session is created
on the active Brocade Virtual ADX, the active Brocade Virtual ADX synchronizes its session
table on the BPs to match the BPs on the standby Brocade Virtual ADX. Synchronization of a
session involves session creation, session deletion, and age updates. No CLI commands are
required to invoke session synchronization from the active Brocade Virtual ADX to the standby
Brocade Virtual ADX.
• Performs health checks. The active and standby Brocade Virtual ADX devices perform Layer 2,
Layer 3, Layer 4, and Layer 7 health checks independently.
• Processes Hello messages.
If the active Brocade Virtual ADX fails, the standby Brocade Virtual ADX becomes active and
immediately takes over the processing of the SLB traffic. Because the sessions were already
synchronized from the previously-active Brocade Virtual ADX, failover is transparent to users.
Hot Standby HA configuration modes
Hot-Standby HA can be configured in two different modes as follows:
• Non-Promiscuous mode with default non-shared MAC option
• Promiscuous mode with shared MAC option
Non-Promiscuous mode with default non-shared MAC option
By default, the virtual switch is set to non-promiscuous mode. To perform seamless failover in this
mode, the new active Brocade Virtual ADX sends gratuitous ARPs with its interface MAC addresses
to the adjacent switches or hosts, immediately after a fail over.
In this case, if gratuitous ARPs can be honored by the next hop router or directly connected hosts,
enable the non-promiscuous mode (if not enabled by default) on the receiving data ports.
In the Brocade Virtual ADX CLI, you need not configure optional keyword shared-mac in the server
backup ethernet port vlan-id vlan MAC command.