Exam 918 Database Server Operations

Server operating modes

The database server's operating mode determines what type of task or access the database administrator (DBA) and users can perform on the database, and what type of service the database server can provide.

User permissions for changing the operating mode

On UNIX and Linux platforms, users who are logged in as root or informix can change the operating mode of the database server. If the INF_ROLE_SEP environment variable is set, the database server administrator can also change the operating mode of the database server. The INF_ROLE_SEP environment variable enforces separating administrative tasks by users who run and audit the database server.

Changing the database server mode

On UNIX or Linux, you can use the onmonitor command to change the database server mode.

Offline mode

Offline mode indicates that the server is not running, no shared memory is initialized, and neither the DBA nor users (clients) can access the database server.
If the shared memory is initialized, the server goes to offline mode by executing the following command:

onmode -k

Initialization Mode

Initialization mode is an interim mode that occurs when the server is initialized and moving from offline mode to quiescent mode. To do that use onmonitor | Mode | Startup or oninit -v

Recovery mode

Whenever the server is going from offline to quiescent-mode, single-user mode, or online mode, the server checks the physical log to see if the server was shut down properly or not. If the physical log is not empty, this indicates that the server was not taken offline properly, and the database server initiates a fast recovery. If the physical log is empty, this indicates that the server was taken offline properly, and fast recovery is not needed.

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