Compaq Computer Corp’s Tandem unit is about to hit back at the claims of Unix server vendors over high availability with its own continuous availability campaign. Some companies have promises. We’ve been delivering it for 20 years will be the general lines of the campaign. We wondered why it was keeping so quiet on the issue, but those at the company say they’ve been pre-occupied with Compaq/DEC/Tandem integration issues – some of which they claim are still being nailed down. Hewlett-Packard Co launched its ‘five nines’ initiative earlier this year, promising 99.999% uptime for the future, an effort intended to make its high-end Unix servers as reliable as IBM mainframes. But according to Tandem, it’s not about adding more nines. To demonstrate what it means, it plans to wheel out one customer that has had a Tandem system up and running for eight years without interruption. What most Unix companies, such as HP and Sun Microsystems Inc, mean when they tout high-availability is a lot of expensive, redundant features and planned downtime, Tandem says. None of them – and not the database companies or independent software vendors either – can back-up data as well as enabling users and customers to access it. Systems and software must either be taken down or halted to take a snapshot, unlike its continuously available Himalayas and NonStop SQL/MX database software. Tandem, which is porting its NonStop clustering middleware to Windows NT to take advantage of the expected rise of enterprise NT systems, says its database will compete directly against Microsoft Corp’s own improved SQL Server 7.0 release to provide continuous availability for NT users. After all clustering can be achieved over Ethernet. It doesn’t require a ‘big bus’ interconnect like Tandem’s ServerNet. What’s still not clear, says Tandem, is whether continuous availability is going to show up in general purpose servers or whether it will remain a boutique service. At the software level re-routing technologies are still complex. When chip-level solutions can be found, then general purpose continuous availability is a likelihood, it says. Tandem was formed to enable users to make the transition from batch-processing systems (which could be restarted if they went down) to online transaction processing systems (which by their nature must not go down). Unlike the duplicated system components used in Stratus fault-tolerant servers – now owned by Ascend Communications Inc – Tandem says its NonStop environment offers continuous availability mostly without redundancy by re-routing and other techniques. In its Himalayas only power supplies and disk subsystems are redundant, not system components or CPU boards. Tandem said the application of its clustering and availability technologies throughout the Compaq product lines is still being worked out. Although it’s moving off the MIPS architecture and heading to Intel, NT and DEC Bravo and SCO Unixes, it declined to say whether the vanilla ServerNet interconnect will be ported to the Alpha RISC.
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