Oracle’s Exalogic – Private Cloud or Modern Mainframe?

Oracle CEO Larry Ellison has been notoriously critical of cloud computing - or at least of the way in which the term "cloud" has been applied.  He often has expressed his frustration when "cloud" is applied to long established patterns such as software as a service (SaaS), especially when this is done by  While there's widespread agreement that "cloud" has become a faddish, over-hyped and often abused term, some have speculated that Ellison's obvious frustration has been fueled by Oracle's inability to fully engage in the cloud computing excitement prior to the conclusion of the Sun acquisition.

Sun's assets included the Java application platform along with complete server and storage hardware technologies, which - combined with Oracle's dominant database and packaged applications stacks - provided Oracle with an integrated software and hardware solution more complete than we have seen in a generation.  Not surprisingly, Oracle has now revealed that its cloud strategy leverages these unique assets - in the form of the "Exalogic Elastic Cloud" hardware/software appliance.

Exalogic is based on a similar architecture to Oracle's successful "Exadata" database machine, which combines smart storage technology, solid state disk, infiniband networking, and Oracle clustered database technology.  Customer testimonials support Oracle's initial claims of dramatic increases in database throughput - the tightly integrated hardware/software architecture does seem to deliver superior price/performance ratios, and raise the ceiling on overall database performance.

Like the Exadata database machine, Exalogic includes high speed infiniband networking and tightly integrated hardware.  However, it is optimized not for IO-intensive workloads, but for compute-intensive processing, in particular for Java-based applications such as those running on Oracle's WebLogic application server.  A fully configured Exalogic server consists of 30 compute nodes with a total of 360 CPU cores and 2.8 TB of RAM.  Storage servers provide 960 GB of Flash Solid State Disk and 40 TB of spinning disk.   All of this is connected via high speed 40 Gb/sec Infiniband switches. 

The software stack for Exalogic includes Oracle Enterprise Linux - derived from Red Hat Linux tree - or Solaris as the operating system.  Although any Linux or compatible software can run on top of the OS, Oracle provides optimized versions of JRockit or Hotpot Java Virtual Machines, WebLogic and the Coherence distributed data cache. Exalogic is, of course, compatible with Oracle's Enterprise Applications, including the traditional 12i, Siebel and PeopleSoft suites, as well as the upcoming Fusion applications.

The first release of Exalogic omits some of the very features that Ellison identified as essential elements of a true cloud computing environment.  In particular, Exalogic version 1 does not support Oracle Virtual Machine (OVM) or, indeed, any virtualization layer.  Instead, all applications run directly in the physical hardware.  For instance, one might run a large WebLogic cluster across multiple Exalogic compute nodes working with one or more Oracle RAC databases running on an Exadata database machine.

At Oracle OpenWorld, Exalogic product managers said support for Oracle's OVM virtualization layer will be forthcoming over the next 12-18 months, followed by a full-fledged cloud management layer apparently inspired by Amazon's Elastic Compute Cloud (EC2).

Without a virtualization or cloud management layer, it's hard to accept that the Exalogic system represents a true private cloud.   For now, it's far more like a 21st century mainframe than a private cloud appliance.  Nevertheless, Oracle has a clear roadmap towards providing an Amazon-like cloud on the Exalogic platform.  In the meantime, Exalogic seems to be a compelling alternative to existing "big iron" systems - both in terms of overall capacity and price/performance - while providing a roadmap to a fully realized private cloud.