Thank you for the added detail confirming Oracle install should not go on shared storage. In several of your last points you imply the RAID (shared SCSI) is more vulnerable to network outages than the local storage on each node. Why is this? Is the shared SCSI on a "network" in contrast to the local disks and thus more susceptibile to network glitches? In my env the RA8000 (RAID unit) is adjacent to the 2 nodes of the cluster. Thank you again.
I apologize for any confusion. RAID by itself is not more vulnerable to network outages than local storage. In fact, RAID devices connected directly to a server through a SCSI bus are very reliable and robust. So it really depends on how the RAID devices are connected to your server. If they are connected through a network, then yes, they are susceptible to network glitches. For instance, I can have RAID devices for my Novell servers. By installing Novell on my NT server, I can access these devices. But I have now introduced Novell software, internet protocols with network layers, and other hardware into my configuration. Each of these has a chance of failure, and any failure can bring down my database. Having locally attached storage reduces the risk of failure by reducing the number of points of failure.
I've seen only a few solutions implemented to date that handle "network" or shared storage for Oracle databases. These solutions are implemented in a Storage Area Network (SAN). These SANS are often a vendor supplied solution. I know that Oracle has been working with Compaq on a SAN solution that is supported with Oracle databases. And as I've iterated before, unless I was working on one of these supported solutions, I would stay away from shared storage.
For More Information
- What do you think about this answer? E-mail us at editor@searchDatabase.com with your feedback.
- The Best Oracle Web Links: tips, tutorials, scripts, and more.
- Have an Oracle tip to offer your fellow DBA's and developers? The best tips submitted will receive a cool prize--submit your tip today!
- Ask your technical Oracle questions--or help out your peers by answering them--in our live discussion forums.
- Ask the Experts yourself: Our Oracle guru is waiting to answer your toughest questions.
This was first published in May 2001