Do you know what downtime costs?

Is it possible to keep computer systems up and running 100% of the time? It is, but the cost and effort required are such that for the vast bulk (99.99999%) of people and businesses, high availability is sufficient.

As mentioned in the previous Industry Insight, one company's high availability is another's unacceptably high level of outages.

Think of the JSE, which experienced a half-day outage in mid-July. For most organisations, this would not be a problem. For the JSE, which has thousands of companies and other organisations depending on it, it was a catastrophe. Millions, even billions, were lost on the day, and the stock exchange's public image took a massive hit.

For the record, there is only one computer system that is available 100% of the time: that is the one that drives the US Department of Defense, and it is self-explanatory why it is always up and running. It is so robust that it could survive a simultaneous nuclear strike on five US cities. To design a system of such resilience was quite beyond the scope of any one vendor, and the US government worked with the cream of the IT industry to ensure the design, implementation and maintenance of the system.

However, for the rest of us, high availability is a relative term, and a little downtime can be tolerated.

Or can it? In a world of 24x7 global trade, with the Internet as the shop window, all indications are that any downtime today is a no-no.

Executives are almost always stunned when they add up all the costs - direct, indirect and opportunity - of system downtime.

Most businesses would hardly bat an eyelid if told their systems would be down for a certain number of hours a year.

But work on this industry formula and it soon becomes clear that downtime is costly:

Take the average sales lost during an hour of system downtime during business hours, then add the total hourly wage (including benefits) of all employees that are idle during that hour of downtime. Now multiply this figure by the estimated number of hours of system downtime during a year. Finally, multiply the result by two to take into account the costs of this lost employee productivity, lost business reputation, and lost business - both now and in the future - from lost customers.

High availability is a relative term, and a little downtime can be tolerated.

Raul Garbini is director of Edgetec

For the purposes of this Industry Insight, I will look at the IBM System i, widely regarded as the most reliable business system in the industry, with reliability as high as 99.95%.

But read this extract from the IBM Redbook, Clustering and IASPs for Higher Availability on the IBM eServer System Server: "According to one IBM study, the System i server averages 61 months between hardware failures. However, even this stellar record can be cause for availability concerns. Stated another way, 61 months between hardware failures means that nearly 67% of all System i servers can expect some type of hardware failure within the first five years."

Also look at two industry comments:

* The Hurwitz Group says that after the loss of a system for a week, 43% of businesses never reopen and another 29% close within two years.
* Gartner reports that 93% of all companies that experience significant data loss are out of business in five years.

This is unplanned downtime, but amazingly, less than 10% of all downtime can be attributed to unplanned events, with the other 90%-plus related to planned events.

Now, it might be thought that planned downtime is OK, but increasingly, given the imperatives of an always-on world, this is no longer the case.

Planned downtime occurs in all businesses, and can be attributed to many business events: backups, system maintenance, such as file reorganisation, software upgrades and data conversions, IBM software upgrades, new application software installs, hardware upgrades and system migrations.

Irrespective, though, of what causes downtime and whether it is planned or not, the fact is that unavailable systems compromise many businesses, and they need a mechanism to address this.

In the next Industry Insight in this series, I'll start looking at how to prevent system downtime.

* Raul Garbini is director of Edgetec.