# F

## Forecasting

Avantra includes a feature called forecasting which is implemented for many Avantra Checks. In fact, it is implemented wherever it is possible. A check requires a resource to be monitored, i.e. something where usage in percent of the maximum available resource space can be calculated.

An example of such a resource-related check is the `FILESYSTEMS` check. A file system has a size and an amount of space that is used. Therefore, the usage in percent is calculated. Now if the used space of a file system grows fast, but is still below the usage thresholds, the used space may be filled very quickly so it may be hard to react in time before the usage threshold related check will give you a Warning status.

Forecasting takes the job to inform you of heavy resource consumption before the resource is full. It will use the previous usage values to interpolate into the future, how long it will take – assuming the usage will continue to grow uniformly – until the resource space available is exhausted. Similar to the two Warning and Critical usage thresholds, each check has two thresholds for forecasting: a Warning (…ExWarn) threshold with a default value of 12 hours, and a Critical (…ExCrit) threshold with a default of one hour. To interpolate into the future, forecasting will always take the usage values of half of the exhaustion threshold past from now, so per default, it will look 30 minutes back for the Critical threshold.

An issue with forecasting is to prevent false alerts, so a growing resource needs to be growing for a certain time, otherwise, a false alert will be reported too often. Additionally, forecasting will be inactive if the usage of a resource is below 50 %.

Forecasting is available for the following checks: ADA_DATAAREA, ADA_LOGAREA, DB2_FSLOGARCH, DB2_LOGUSAGE, DB2_TABLESPACES, FILESYSTEMS, HDB_Disks, MSS_DBUSAGE, MSS_LOGUSAGE, ORA_FSLOGARCH, ORA_TABLESPACES, SYB_DataSpaces, and SYB_LogSpaces

Forecasting is also available with Performance data for those resources where it is useful. Whenever you select the time range of a Performance chart to extend into the future, the data is extrapolated accordingly. It is also available in the Service Level Reports unless opted-out during generation.