Oracle RAC and Grid Q&A With The Experts
Q&A about RAC and Grid with the RAC Experts
I recently got the opportunity to sit down and talk to two RAC gurus and learn what RAC is and how it relates to Oracle’s Grid technology. Listen to the discussion with Philip Newland and Scott Jesse, both from Oracle Corp. Philip is a technical manager with Oracle’s RAC Pack team and Scott is an Oracle Support Services Manager for the RAC Assurance Team. Scott is also the co-author of two Oracle Press books, “Oracle9i for Windows 2000 Tips & Techniques” and “Oracle Database 10g High Availability with RAC, Flashback & DataGuard”.
There were plenty of questions asked and answered. Here are five important questions. Listen to the podcast to hear the rest.
What does Oracle mean by Grid?
An Oracle Grid allows you to add computing capacity, CPUs or storage, on demand as needed without pre-purchasing monolithic hardware. On an Oracle Grid, you can add capacity one cheap PC at a time.
There is no product for sale called Oracle Grid. You can’t just walk into a store and buy a grid. Oracle Grid is a technology composed of several innovative Oracle products.
What components make up an Oracle Grid?
Oracle Real Application Clusters (RAC) allows Oracle customers to add database capacity (by adding servers) to an existing cluster. RAC allows a database to be spread across multiple servers. You can dynamically add and remove nodes (servers) as required.
RAC allows an application to transparently scale, add performance and be available 24/7. RAC can be very affordable to scale because it allows you to add cheap servers when you need them.
Oracle Automatic Storage Management (ASM) eases storage management by abstracting file systems to where DBAs need them. ASM also allows consolidation of storage so that applications that need storage have it available when they need it.
Oracle Clusterware provides the intelligence for a cluster. A cluster is a series of servers acting as a single entity. Clusterware provides the management and monitoring of a cluster.
Oracle Clusterware is not limited to providing scalability and high availability for Oracle Databases. With Oracle Clusterware, you can provide these services for third-party databases, application servers and pretty much any other kind of application.
Cluster File System
Oracle Cluster File System (OCFS & ACFS2) allows an Oracle database cluster to share disk across many servers. OCFS ensures that Oracle sees a consistent image of the disks on each server.
Does RAC work with Oracle Standard Edition?
Oracle Standard Edition, the edition of Oracle for the SMB market, comes with a license for a 4 node RAC cluster. A standard edition license allows up to 4 CPU sockets in a cluster. Those 4 sockets may be in a single server or in two, three or four servers. As long as your cluster does not exceed 4 sockets, RAC is included as part of your Standard Edition License.
Standard Edition does not limit the size of your database in anyway so as long as the processing power for a four socket configuration suits your needs, this can be a great way to save. If you need to scale to a larger cluster, Standard Edition can easily be upgraded to Enterprise Edition allowing you up to 1000 nodes.
Standard Edition RAC configurations are required to use ASM. Because ASM saves time and effort, this is not really a limitation but more of a method for Oracle to help you ensure your success.
How do I monitor my Grid?
Oracle provides both DB Control and Grid Control for monitoring and managing your databases. DB control is a web based tool that allows you to manage one database at a time. Oracle Grid Control allows you to manage entire grids and is an add on package. Grid Control can simplify all of your grid management tasks.
Can I mix and match hardware?
Yes. Oracle expects that vendors are improving hardware constantly and that customers will need to upgrade hardware over time. Rather than force customers to maintain a single vendor or configuration, Oracle RAC will work across various hardware configurations. While one server may be a single CPU and 4GB of RAM, another server in the same cluster can be 4 CPUs (with dual cores) and 16GB of RAM.
The only requirement is that the Operating Systems must match: Windows to Windows, Linux to Linux, 32 bit to 32 bit, etc.
Grid Computing – Oracle allows you to scale by tying together cheap hardware in a cluster allowing multiple servers to act as one. Oracle provides the software that enables database grids (via RAC) as well as storage grids (via ASM and OCFS). Oracle’s Grid allows a business to start as large or small as they need, spending money on hardware and other system resources only when it is actually needed. RAC and Grid is transparent to the application allowing painless and immediate scaling when required.
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