SELECT ln.name, gets, misses, immediate_gets, immediate_misses
FROM v$latch l, v$latchname ln
WHERE ln.name IN ('redo allocation', 'redo copy')
AND ln.latch# = l.latch#
/

select name,value from v$sysstat
where name = 'redo log space requests';

/*
Value should not be > 0
*/