FAST_START_MTTR_TARGET

FAST_START_MTTR_TARGET enables you to specify the number of seconds the database takes to perform crash recovery of a single instance.

As we know the FAST_START_MTTR_TARGET initialization parameter specify the maximum no. of seconds for data to stay in memory before DBW0 can write this data to actual data file.

The default is 300 seconds (5 Minutes). and maximum we can give 3600 ( 1 Hour).

Also since there can be upt to 10 DBWn processes a DBA can start and default is only one. 

LOG_CHECKPOINT_INTERVAL (in oracle 8.0)

LOG_CHECKPOINT_INTERVAL specifies the frequency of checkpoints in terms of the number of

redo log file blocks that are written between consecutive checkpoints.

LOG_CHECKPOINT_INTERVAL (in oracle 8i)

LOG_CHECKPOINT_INTERVAL specifies the frequency of checkpoints in terms of the number of

redo log file blocks that can exist between an incremental checkpoint and the last block

written to the redo log. This number refers to physical operating system blocks, not

database blocks.

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.

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.

if i remove LOG_CHECKPOINT_TIMEOUT from pfile the parameter appears with the value of 1800, so i set that to 0 in the pfile.