Following the trend towards fault-tolerant software offerings, Mountain View, California-based Objectivity Inc has launched a Fault Tolerant add-on option on top of a 3.8 cut of its Objectivity/DB database. Critical enabling technology is a new feature that supports automated recovery from a hardware failure, rolling back transactions and freeing locks if the system dies. Only limited partitioning was previously available. The Fault Tolerant option requires no change in the programming model and existing applications can also take advantage of the option when they move up to release 3.8. The company’s offering comes hard on the heels of rival Versant Object Technology Corp’s Fault Tolerant Server module (CI No 2,685). Objectivity said its technique, which replicates processes, lock servers, data dictionaries and catalogues across distributed instances of the database, is fundamentally different to Versant’s approach, which is based on duplication of data. This, claims Objectivity, impairs read performance, it means it has to write all data twice and it puts the integrity of data at risk. Under the Versant model, Objectivity explained, production and failover versions of a database serving local clients could get out of sync if the wide area network separating them goes down.
Historical account
Clients local to the production system notice nothing wrong and continue to log transactions against the production database. The transactions don’t make it to the duplicate database because the wide area network is down. Over a local area network too, only one point of failure would be tolerated under the Versant scheme, Objectivity observed. Hardware-based fault-tolerant systems – duplicated processors, RAID or uninterruptible power supplies – would be far more appropriate to use in the situations, Objectivity said. Its mechanism enables any instance of a database distributed over an enterprise network to know where any piece of data is stored, but records only key information – such as account balance in an automated teller – at each site. Historic account information would be held only at a local site under the Objectivity model. If the network goes down, local sites can continue logging transactions using data stored there and its locks and data dictionaries can be updated by (and update) the remaining i nstances of the database when it comes back on line. The finer-grain system will prove more attractive than Versant’s approach, Objectivity argued. Up under most Unixes, Windows NT and Windows from October, VMS and other Unixes by the end of the year, Objectivity 3.8 starts at $3,000 for a single server. Upgrades are free to customers with support contracts. The Fault Tolerant option costs from $750. Meantime, Motorola Inc has picked up Objectivity/DB, which it will use to develop the monitoring and controlling software for its Iridium satellite-based telephone system. Most of Objectivity’s customers are using the database embedded within other application offerings. Data processing departments simply aren’t ready for object databases yet, it said. Objectivity is currently working on a new release of its core database due in the first quarter of next year. Dubbed Kilimanjaro – the mountain can be seen from a greater area than any other feature on Earth – the release will provide continuous availability features as standard, the company said. Much of the technology promised for a late summer version 4.0 release was bundled in version 3.8, it said. The company is also working on a Macintosh release of its database, but that has apparently not yet gone into beta test.
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