Oracle Database Tips by Donald Burleson

Oracle10g Grid Computing with RAC
Chapter 8 - RAC Administration

Implementing the Oracle Hardware Assisted Resilient Data (HARD) Initiative for the OCR

Oracle program algorithms validate and add protection information to the database blocks and once passed to the disk, the protection information is validated by the HARD compliant storage device. In this manner HARD prevents corruptions from being introduced into the I/O path between the database and storage and therefore eliminates a large percentage of failures that the database industry has previously not been able to prevent. While RAID, in its many flavors (0, 1, 1+0, 5) has gained a wide following with system operators by ensuring the physical protection of data, the HARD algorithm implementation takes data protection to the next level by going beyond protecting physical bits, to protecting business data.

The HARD algorithms were first made available in the Oracle9i Database and have been extended into the Oracle Database 10g. The validation in Oracle Database 10g is more comprehensive and all file types and block are inoculated by HARD including database files, online logs, archive logs and backups. In addition the use of ASM enables HARD without having to use raw disk devices. With the cooperation of hardware vendors HARD support is being offered in conjunction with many of the major storage arrays.

The classes of data corruptions that Oracle addresses with HARD include: