Can any one explain me the difference between vertical scalability and horizontal scalability?
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Horizontal scaling for Oracle
This is called "horizontal scaling", or the "scale out" approach, whereby small server blades are genned-in to an Oracle RAC cluster over a high-speed interconnect. Horizontal scaling requires Real Application Clusters and also provides the benefit of guaranteed continuous availability.
Vertical scaling for Oracle
We also see the "scale up" approach (the vertically scalable architecture) whereby server resources (CPU, RAM, Disk) can be added into a single, monolithic server. Examples include the HP Superdome (64 CPU), the Unisys ES7000 (32 Processors) The Sun Sun Fire and the IBM X Series.
Vertical scaling has several benefits over horizontal scaling for Oracle databases:
* RAC is not required
* Machine resources (especially CPU) are instantly available for sharing
* A single-server requires less overhead and management
The Sun architecture has broken the Oracle data warehouse TPC-H World record using a vertical scalable architecture.
"Running on a single Sun Fire™ 25K server with 72 UltraSPARC IV+ 1.5 GHz processors and the Solaris™ 10 Operating System (OS), Oracle Database 10g Release 2 with Automatic Storage Management achieved a record-breaking performance of 105,430.9.
Oracle Database 10g Release 2 repeatedly demonstrates its superior fit in demanding data warehouse environments, " said Richard Sarwal, vice president of Server Performance, Oracle. "The addition of this benchmark helps to prove that no matter how much our customers' data warehouses grow, the Oracle Database will continue to deliver the best, most consistent database performance."