Cisco Cisco Evolved Programmable Network Manager 2.0 インストールガイド
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The following figure shows the main components and process flows for an HA setup.
An HA deployment consists of a primary and a secondary server with Health Monitor (HM) instances (running as application
processes) on both servers. When the primary server fails (either automatically or because it is manually stopped), the secondary
server takes over and manages the network while you restore access to the primary server. If the deployment is configured for
automatic failover, the secondary server takes over the active role within two to three minutes after the failover.
processes) on both servers. When the primary server fails (either automatically or because it is manually stopped), the secondary
server takes over and manages the network while you restore access to the primary server. If the deployment is configured for
automatic failover, the secondary server takes over the active role within two to three minutes after the failover.
When issues on the primary server are resolved and the server is in a running state, it remains in standby mode and begins
syncing its data with the active secondary server. When a failback is triggered, the primary server again takes over the active
role. This role switching between the primary and secondary servers happens within two to three minutes.
syncing its data with the active secondary server. When a failback is triggered, the primary server again takes over the active
role. This role switching between the primary and secondary servers happens within two to three minutes.
Synchronizations between the primary and secondary servers fall under two categories:
•
File changes—File changes are synchronized using the HTTPS protocol and include changes in report configurations,
configuration templates, TFTP-root directory, administration settings, licensing files, the key store, and so forth. File
synchronization is done in:
configuration templates, TFTP-root directory, administration settings, licensing files, the key store, and so forth. File
synchronization is done in:
–
Batches—For files that are not updated frequently, such as license files. These files are synchronized once every
500 seconds.
500 seconds.
–
Near real-time—For files that are updated frequently. These files are synchronized once every 11 seconds.
•
Database changes—These changes are related to configuration, performance, and monitoring data. These are synchronized
using Oracle Recovery Manager (RMAN), which creates the initial standby database, and Oracle Active Data Guard, which
synchronizes the databases when a change occurs.
using Oracle Recovery Manager (RMAN), which creates the initial standby database, and Oracle Active Data Guard, which
synchronizes the databases when a change occurs.
As part of the synchronization process, the primary and secondary servers exchange the following messages:
•
Database Sync messages—Includes all the information necessary to ensure that the databases on the primary and secondary
servers are running and synchronized.
servers are running and synchronized.
•
File Sync messages—Includes frequently-updated configuration files. These are synchronized in batches or near real-time,
as explained previously.
as explained previously.
•
Process Sync messages—Includes information about whether the application- and database-related processes are running.
These messages fall under the Heartbeat category.
These messages fall under the Heartbeat category.
•
Health Monitor Sync messages—Includes information about reports, network, system, and Health Monitor failure
conditions.
conditions.
Primary Server
Secondary Server
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Active
Database
Data Guard Broker
Standby
Database
Active
Database
Standby
Database
DB Sync
File Sync
Primary
HM
Primary
Server
Secondary
HM
Secondary
Server