After you install the Storage Provisioning Option, Backup Exec can predict the usage of disk space on the storage arrays. You can configure Backup Exec to send an alert when it predicts that the amount of available disk space for all storage arrays is low. The alert provides information about whether the current disk space resources are sufficient, and can help you plan when to increase disk space.
Backup Exec gathers sample data for statistical analysis. For example, you can use the defaults to let Backup Exec gather data for a one-week period of 24-hour days. To ensure statistical accuracy, by default Backup Exec keeps 35 sample groups of data. Backup Exec examines the job history data for each sample group and uses the new data to recalculate the disk usage trends.
Backup Exec uses the sample data to estimate the rate at which future jobs will use space in the disk array. Backup Exec computes the statistical average for previous usage and determines any upward trends or downward trends. Backup Exec also calculates the amount of used disk space that becomes available as the overwrite protection periods expire for previous backup sets.
Backup Exec combines these estimates with the amount of available disk space on storage arrays. Backup Exec can then predict how much time remains before the disk space on all storage arrays is depleted.
The accuracy of the prediction is reduced if any of the following conditions occur: