Hi Hameed,

now i wanted to know how to check is the above db started with the pfile ?
show parameter pfile

this will tell you whether database is opened with pfile or spfile

If you are on UNIX then you can check the number of dbwr processes started using the below command.

ps -ef|grep ora_dbw
If you are on Windows ..

select * from v$bgprocess where name like 'DBW%' and PSERIAL# <> 0
As par Oracle documentation, you can set value as 1 (default) or CPU_COUNT / 8 whichever is grater.

Please click here to read dbwr tuning tips from Burlison.

Thanks,