Error Message

The "ORA-01578 ORACLE data block corrupted" is occurred at Oracle Alert.log during crash/instance recovery.

The excerption of Oracle Alert.log:

...

Corrupt Block Found
Corrupt block relative dba: 0xnnnnnnnnf (file # string, block # string)
Reading datafile '/dev/vx/rdsk/xxxdg/rxxxvol' for corruption at rdba: 0xnnnnnnnn (file # string, block # string)
Reread (file # string, block # string) found same corrupt data (no logical check)
...

If Customer do use the 4KB offset logical volumes and their Oracle database block size is greater than 4K then, A single Oracle block will be split across the stripe boundaries. It means that a single Oracle block may spans two disks.

If the server is halted or crashed during I/O operations that spans disks, then Some part of the block may be written while the other part is not. This will results in fractured data blocks, It will make the database unusable.

Oracle recommends officially that a zero offset should be used in case Oracle database files are resides on raw logical volume to prevent the fractured block corruptions and I/O performance overhead as a proactive step.

To align with Oracle's recommendation and to improve Customer Total Experience, Veritas would like to inform our customers of the following important note:

From VxVM point of view, The default value is dsvm, which requires that the first 4k blocks(4KB offset) are skipped when writing to the volume. If the value dsvmprime is specified, the volume can have data written to it from the first block(zero offset).

To prevent the fractured block corruptions by Oracle and I/O performance overhead even though the corruption which may occur is not due to any known issue in the VxVM product stack, Set the devsubtype variable to 'dsvmprime' on VxVM/CVM volumes + AIX platform to use the zero offset for storing Oracle data files.  It is still valid regardless of what Oracle/Storage Foundation for Oracle RAC release.

Applies To

Storage Foundation for Oracle RAC 6.0.5

Oracle RAC 11g Release 2 (11.2.0.4.0) - db_block_size = 8192 (8KB)

IBM AIX 7.1 TL3

Raw CVM volume with dsvm devsubtype for storing Oracle data files