Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable{mso-style-name:"Table Normal";mso-tstyle-rowband-size:0;mso-tstyle-colband-size:0;mso-style-noshow:yes;mso-style-parent:"";mso-padding-alt:0cm 5.4pt 0cm 5.4pt;mso-para-margin:0cm;mso-para-margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:10.0pt;font-family:"Times New Roman";mso-ansi-language:#0400;mso-fareast-language:#0400;mso-bidi-language:#0400;}While it’s true that clustering is targeted primarily atproviding high availability, advanced clustering solutions are not just about HA. They can also make lifeeasier for IT administrators.

Think about it. Clustering enables you to automaticallystart and stop applications within a cluster. If you put a lot of applicationsthat are across a lot of servers into a single cluster, then you also have avery easy way to...

Author’s Note:  It’s come to our attention that while this is primarily a technical blog geared towards current users of Veritas Cluster Server (VCS), there are some readers of this blog with little background in clustering for availability.  So with that in mind, we begin a series of posts which we hope will provide some foundation knowledge for those aspiring to HA Gurudom.

Nod if any of this sounds familiar …

Your company demands IT services that pretty much never go down. After all, business availability and IT service availability are inextricably linked today.

But things happen. Like hardware failures. Power outages. Upgrades. Patches. Shrinking budgets. And other natural and man-made disasters. Your basic Career Limiting Event™ when the revenue generating or customer facing application goes down.

Given such an environment, is it even possible to achieve application dial tone and the like?

Sure....

VCS has long provided the ability to create service group dependencies by which a VCS cluster can be directed to start one service group before another, keep service groups together (or separate) on one node, and the like.  This is great for applications running in the same cluster, but what if there's an application running in one cluster that's got a relationship to a service group running in a different cluster?  Worse yet, what if the clusters are on different OS platforms?  The RemoteGroup resource introduced with VCS 5.0 was built to address these situations.

Let's look at a scenario where we have a VCS 5.0 cluster running Linux, with an Apache web server under control of  VCS.  The web server accesses data held in an Oracle database running on Solaris, and made highly available with VCS 5.0.  This is an example of a simple two-tiered application.  The web server isn't functional without the Oracle database, and the Oracle...