Data Warehousings Big Sleep
Dormant data—information that never has and never will be accessed—can give a data warehouse a heart attack. Could your systems be at risk?The cost of storage may be falling, but are you reaping the benefits? Probably not, according to Bill Inmon, creator of the data warehouse concept. "Were using storage at a rate that far surpasses the rate at which prices are dropping," he says. Corporate data warehouses, which collect far more detail than standard databases and retain information historically, account for a significant proportion of storage costs. But the usefulness of a warehouse doesnt necessarily increase as you stuff more data into it. Rather, many data warehouses suffer from an abundance of "dormant data"data that has never been accessed and probably never will be. Such excess "clogs up the efficiency of data for all users," says Inmon. "If you get enough cholesterol in your bloodstream, you have a heart attack. Its the same with dormant data." Superfluous data can also aggravate the complexity of storage systems, which are becoming increasingly hard to manage.
Besides performance, theres cost to consider. Disk-storage vendors like to advertise falling prices, but "the ratio of disk to nondisk prices has been fairly constant for almost 10 years," says Inmon.