Call for Oracle support & training (800) 766-1884
Free Oracle Tips

Corporate Oracle Training
Custom Oracle Training
Oracle New Features Training
Advanced Oracle DBA Classes
Oracle Tuning Courses
Oracle Tips & Tricks
Oracle Training Links
Oracle Training Links
Oracle Training Links

We are top for USA Oracle Training Clients


Free Oracle Tips


Free Oracle App Server Tips


Oracle support

Oracle training

Oracle tuning


Remote Oracle

Custom Oracle Training

Donald K. Burleson

Oracle RAC Tips

Veritas CFS

The VERITAS Database Edition/Advanced Cluster for Oracle9i RAC enables Oracle to use the CFS. The Veritas CFS is an extension of the VERITAS File System (VxFS). The Veritas CFS allows the same file system to be simultaneously mounted on multiple nodes. Veritas CFS is designed with master/slave architecture. Any node can initiate a metadata operation (create, delete, or resize data) and the master node carries out the actual operation. All other (non metadata) I/O goes directly to the disk.

A distributed locking mechanism, called the global lock manager (GLM) is used for metadata and cache coherency across the multiple nodes. GLM provides a way to ensure that all the nodes will have a consistent view of the file system. When any node wishes to read data, it requests a shared lock. If another node wishes to write to the same area of the file system, it must request an exclusive lock. The GLM revokes all shared locks before granting the exclusive lock and informs reading nodes that their data is no longer valid.

CFS is used in DBE/AC to manage a file system in a large database environment. When used in DBE/AC for Oracle9i RAC, Oracle accesses data files stored on CFS file systems with the ODM interface. This essentially bypasses the file system buffer and file system locking. This means that only Oracle handles the tasks of buffering data and coordinating writes to files and not the GLM, which is minimally used with the ODM interface.

For more information, see the book Oracle 11g Grid and Real Application Clusters 30% off if you buy it directly from Rampant TechPress . 

Written by top Oracle experts, this RAC book has a complete online code depot with ready to use RAC scripts.





Oracle performance tuning book



Oracle performance tuning software

Oracle performance tuning software
Oracle performance Tuning 10g reference poster
Oracle training in Linux commands
Oracle training Excel
email BC:

Copyright © 1996 -  2014 by Burleson Inc. All rights reserved.

Oracle® is the registered trademark of Oracle Corporation.