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Continuous Availability For Your Company Networks
alternative for middleware. Point of sale solutions, CRM tools, and even BlackBerry messaging environments implement a similar prescription, utilizing completely different technologies for each layer in the application stack. Having such an approach to running a business continuity solution for your enterprise application ecosystem has several drawbacks. First and foremost, one must be aware of the cost implications of utilizing different technologies within a continuous availability or DR architecture. The most obvious cost is the equity outlay for the hardware/software itself. By choosing (or being forced) to apply different solutions from different vendors, there is no possibility to leverage economies of scale. Most hardware and software companies offer volume based pricing enticements for larger order sizes, but this possibility is obviously squandered when various alternatives from different vendors are employed. Additionally if each solution leverages different underlying hardware, disk, or OS technologies, an even larger total cost of ownership will be noticed. Of course cost extends beyond just hardware and software to include implementation, coaching, and continuing management costs. Think aboutdeploying even a pretty basic, three tier application architecture. In the online web ordering example discussed previously, one would need to take on the somewhat unnerving task of learning about not only the intricacies of SQL clustering, but also deployment and management of network load balancing and any middleware components needed. Every time a new variation of any of these solutions is made, theres the additional cost of relearning a new technology. Then contemplate the complexity of integrating differing availability technologies from multiple vendors. Are they guaranteed to interoperate with one another? Is such interoperability built in (unlikely) or will some degree of customization and manual scripting (very possibly) be needed, so that every tier can communicate with the other tiers? If custom scripting is required, what happens when even a single part of the availability architecture changes? Will extra, custom consulting work be necessary to develop and re test existing scripts? Last but not least, if and when something breaks down, whose responsibility is it to identify the root cause? With different solutions from different vendors, one must be wary of the inevitable finger pointing that may result when things go wrong. Naturally one alternative is to simply not integrate the solutions, after all, so long as each portion is doing its job, isnt it safe to assume that the entire system is operational? Not necessarily. Consider for example the deployment of a multi tier, distributed architecture across physical sites for DR purposes. If the entire, primary production site fails, will the servers start up in the correct order and fashion at the remote site, or will some degree of interaction be needed from an administrator? Now examine the more probabletype of failure, when just one component instead of an entire site fails. Unless youve deployed a combined High Availability Disaster Recovery solution, chances are that the single failed component will resume operations at the DR site. But in most cases, the latency between sites will be too high for any multi tier application to function properly. In this situation, its best to actually fail all of the components across to the remote site as a single, cohesive unit. But once again, how does this coordination take place? Either we are back to scripting the failover in some manner, or else some hands on administrator involvement is needed. When that takes place, recovery times inevitably increase; when recovery times increase, so does the bottom line cost of the outage to the business. Article Directory: http://www.articledashboard.com Mandy Gee writes about Business Continuity and Disaster Recovery. |
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