Roll-up/age-out scheme
NetIM reduces the amount of storage space needed for metric data by consolidating it over time. Consolidation allows historical data for a longer period to be saved for later use.
Data for built-in metrics is consolidated in two ways:
• Age-out—Deletes metric data older than a specified threshold. Metric data that are configured to age out are retained in their original form (as raw samples) until the specified retention threshold is reached. Data that falls outside of the retention threshold is deleted. The data retention thresholds for age out are listed in the following table. These thresholds are configurable in
Rollup wizard.
Default value | Minimum value | Maximum value |
31 days | 1 day | 31 days |
• Roll-up—Consolidates metric data into larger, less granular time intervals using one or more mathematical algorithms. Roll-up retains data over a longer time period than would otherwise be possible, although at increasingly reduced fidelity as the data ages. When roll-up is performed, metric data is retained for an epoch (raw, hourly, daily, or weekly samples) until the specified retention threshold for that epoch is reached, after which it is deleted.
For most metric classes that can be rolled up, roll-up retains up to three of the following values, based on your selections in
Rollup wizard:
– 95th percentile of values per sample time
– 98th percentile of values per sample time
– Maximum value of all samples
– Mean value of all samples
– Minimum value of all samples
For the Device Availability and Interface Availability metric classes, the only rolled up value will be the weighted average of all samples.
The data retention thresholds for roll up are listed in the following table. These thresholds are configurable in
Rollup wizard.
Data type | Default value | Minimum value | Maximum value |
Raw Data | 30 days | 1 day | 90 days |
Hourly Data | 80 days | 1 day | 168 days |
Daily Data | 50 weeks | 1 week | 104 weeks |
Weekly Data | 264 weeks | 1 week | 264 weeks |
Data for user-defined metrics (those defined using the
Defining a metric class using the User-Defined Metrics wizard) are aged out according to the age out settings in the
Rollup wizard. Rollup does not apply to data collected for user-defined metrics.
Age-out and rollup are performed at regular intervals. Metric data that have been deleted by age-out or rollup cannot be recovered.
For information about which type of data consolidation is used for each built-in metric, see
Built-In Metrics.