Set FAST_START_MTTR_TARGET parameter

Question

Hi experts,
I was set FAST_START_MTTR_TARGET parameter 14. and as per my understanding if i set FAST_START_MTTR_TARGET is 14 , it might mean, it will take 13 second for instance recover.
But when i had to applied it in real environment , it wasn't work. It was take more time. Can you please explain my understanding is rite or not. OR if i was rite then why it's take more time for recover instance.
SQL> sho parameter FAST_START_MTTR_TARGET
NAME                                 TYPE        VALUE
fast_start_mttr_target               integer     0
SQL> alter system set FAST_START_MTTR_TARGET=14 scope=both;
System altered.
SQL> sho parameter FAST_START_MTTR_TARGET
NAME                                 TYPE        VALUE
fast_start_mttr_target               integer     14Reg,
Harshit

Answer 1

Hi,
Firstly 14 seconds is what you would like to achieve. Doesn't mean that this is what you will achieve. This could be because of a number of reasons one of which might be the speed of the disks the database sits on.
By setting this parameter Oracle will checkpoint at intervals to try and keep your mttr to 14 seconds. A low setting isn't necessarily a good thing as you will have more frequent checkpoints which in turns means more I/O. Again this can be quite bad if your database is sitting on low performance disks.
Secondly you need to disable LOG_CHECKPOINT_INTERVAL.
alter system set log_checkpoint_interval=0 scope=both;