check_redolog_mirror 

ORACLE offers the possibility to mirror the online redo log files. SAPDBA can check the presence and validity of the online redo log files and their mirrors (at least 2 members per group should be present). See also check_initial_settings.

Default value: Y

Possible values: Y/N (Y(es) - online redo log group check is executed, N(o) - online redo log group check is not executed).

The setting Y (es) means that, on starting up, SAPDBA issues a warning if one of the members of the online redo log group is not present or invalid. Only then does the initial menu appear.

See also Mirroring Online Redo Log Files.