On 11/14/06, Ram Raman <veeeraman@xxxxxxxxx> wrote:
Hi all, Some time ago there was a discussion on how we would detect the corrupt blocks if the blocks are skipped from being read during RMAN backup because of change block tracking. I was in an Oracle training class and I asked the question to the instructor. His answer was that if the block was not being accessed it could not go corrupt. ie. If the block is changed then it is tracked by Oracle, if it is not accessed and changed how it could go corrupt. Any comments?
If the sector of the brown spinning stuff that the un-accessed block lives on has a defect and causes a physical corruption, the database block may be unaffected. Or if your SAN/Disk Controller/NAS has a hiccup, something bad might happen. ( It *does* happen) This can be used to check for corruptions run { allocate channel d1 type disk; allocate channel d2 type disk; backup check logical validate database; release channel d1; release channel d2; } the view V$DATABASE_BLOCK_CORRUPTION will be populated if corrupt blocks are found. -- Jared Still Certifiable Oracle DBA and Part Time Perl Evangelist