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Frank Hill is the director of manufacturing business development for Stratus Technologies. |
Availability Options
Some production-line applications are more critical than others. The first applications you want back online usually are the ones that need higher levels of uptime protection.
A full analysis of availability products, technologies and approaches is beyond the scope of this article. Suffice it to say, each has its place, its benefits and tradeoffs, and very real differences in the ability to protect against application downtime.
A common way to assess a solution’s efficacy is by looking at its “nines,” i.e. its promised level uptime protection. The chart below shows the expected period of downtime for each level, and how that might translate into financial losses. Note that downtime per year could be a single instance, or spread across multiple incidents. Also note that higher uptime does not necessarily mean a solution is more costly; software licensing, configuration restrictions, required skills, ease of use and management are just a few of the many factors affecting total cost of ownership.
As we mentioned at the outset, most high-availability solutions focus on recovery after failure. Very few are engineered to prevent failure from occurring.
