Use RMAN to avoid the generation of Split Blocks

Split Block: During Hot Backup (that is, when the OS command copies the cp, the OS cp unit is not the data block but the OS block), the data Block is being modified by the user, that is, an Oracle Block contains multiple OS blocks. An OS-Level copy may be a part of an Oracle Block (such as a Header), and the other part is updated and changed by users, as a result, an Oracle Block may be inconsistent. A data block may contain several different versions of OS blocks, which are called Split blocks. The Block here refers to the data block.
The unit of rman is data block, which does not exist. Block-level access is a difference between RMAN and other backup tools.

RMAN backup involves the following simple processes: 1. RMAN reads all data blocks (Oracle block, whether formatted or not there is data) of the data files to be backed up into the input buffer (part of PGA ),
This process is performed in the smallest unit of Oracle block, and there is no OS Block-level copy or backup. Therefore, this process will not produce the so-called "split block.

2. The next important process is the Memory-To-Memory process, that is, when the input buffer is full and then written To the output buffer (which is also part of PGA by default). There will be some things To do in this process.
Oracle first checks whether the oracle block has been used (whether the header information is zero ),
If a data block is not used, the write operation to the output buffer is not performed, and the data block is discarded,
If it is used, and then determine whether there is data (it is estimated that it is also the judgment header information), if it exists, the test and checksum operations will be performed on the data block.
Finally, judge whether the Oracle block header matches the footer and whether it is a split block. If not, write the data to the output buffer,
If it is a split block, back up the block to the input buffer.

3. When the Oracle block written to the output buffer reaches a certain level (full), it is written to the backup location (assumed as a disk ).

Recommended reading:

Basic Oracle tutorial-copying a database through RMAN

Reference for RMAN backup policy formulation

RMAN backup learning notes

Oracle Database Backup encryption RMAN Encryption