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        <Name>The High Availability Database Challenge</Name>
        <Summary>A summary of challenges to high availability in your database</Summary>
        <Description>&lt;p&gt;High availability implies little to no downtime. Downtime results from &lt;u&gt;security&lt;/u&gt; breaches, lack of &lt;u&gt;scalability&lt;/u&gt; or &lt;u&gt;failure&lt;/u&gt; (hardware or software). To achieve high availability you must manage all three characteristics for each layer in the Internet Delivery Stack.&lt;/p&gt;&lt;p&gt;One area of real challenge to this is the Database Layer. This article explains a bit why...&lt;/p&gt;&lt;p&gt;Traditional attempts at High Availability involve replicating information to secondary equipment or locations to be used in the case of failure to the production environment.&lt;/p&gt;&lt;p&gt;This replication though represents significant challenges when it comes to the the database layer of the stack.&amp;nbsp;Because databases often change rapidly and require immediate response, it's difficult (i.e. expensive) to replicate the data to secondary hardware or to another physical buliding.&lt;/p&gt;&lt;p&gt;Enterprise SQL servers (such as from Oracle and Microsoft) provide tools to accomplish replication. This expensive and complex software can allow a collection of physical database servers, even in separate locations, to appear as one large database to the application.&lt;/p&gt;&lt;p&gt;If you're looking for a high-availablity environment make sure you invest properly at each layer in the stack. A highly scalable network doesn't help high-availibility if your database server is prone to a single hardware failure.&lt;/p&gt;</Description>
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