cant set fast_start_mttr_target parameter

[gvillaran]

FAST_START_MTTR_TARGET:
The FAST_START_MTTR_TARGET initialization parameter simplifies the configuration of recovery time from instance or system failure. This parameter lets you specify the number of seconds crash or instance recovery is expected to take. The FAST_START_MTTR_TARGET is internally converted to a set of parameters that modify the operation of Oracle such that recovery time is as close to this estimate as possible.

Note:
You should disable or remove the FAST_START_IO_TARGET, LOG_CHECKPOINT_INTERVAL, and LOG_CHECKPOINT_TIMEOUT initialization parameters when using FAST_START_MTTR_TARGET. Setting these parameters to active values interferes with FAST_START_MTTR_TARGET, resulting in a different than expected value in the TARGET_MTTR column of the V$INSTANCE_RECOVERY view.


other notes :

Whenever you set FAST_START_MTTR_TARGET to a nonzero value, and while MTTR advisory is ON, Oracle Corporation recommends that you disable (set to 0) the following parameters:

LOG_CHECKPOINT_TIMEOUT
LOG_CHECKPOINT_INTERVAL
FAST_START_IO_TARGET

Because these initialization parameters either override FAST_START_MTTR_TARGET or potentially drive checkpoints more aggressively than FAST_START_MTTR_TARGET does, they can interfere with the simulation.

(extracted from tahiti.oracle.com)

I am forgetting something?