Oracle Database Discussions

Hi DBA gurus,

I have a situation where DB is performing slowly.
ADDM analysis and other AWR report findings showing IO is slow.

UNIX Sysadmin folks found that OS block size 1K where it should have been 8K. file systems are created wrongly with 1K OS blocks.

I have lot of Datafiles created in the partitions. What is the way to increase the block size to 8K?

Do I have to recreate the DB if underlying OS block size change?

i have
/oradb1
/oradb2 partitions with OS block 1K size

if UNIX creates new files /oradb3 and /oradb4 with 8K block size what do I need to do to make the change?

Thanks in advance.