Cactidocumentation/Data-Profiles.md

Data Source Profiles

Data Source Profiles define sampling intervals, heartbeats, consolidation functions and archive retention for data sources. A profile controls how an RRD file is created. Selecting another profile does not convert an existing file.

Configure a profile for new data sources

Open Console > Presets > Data Profiles. Create a profile or duplicate an existing one, then set its sampling interval, heartbeat and consolidation functions. Edit its archive rows and aggregation durations for the desired retention before assigning it to new templates or data sources.

Archive settings are read-only when existing local sources use that profile. Duplicate the profile and edit the copy for new sources instead of deleting all graphs to unlock the editor. More rows, series, archives and consolidation functions require more disk space; the profile's displayed estimate is more useful than a fixed size table copied from a different configuration.

Calculate retention

Each RRA row covers the base sampling step multiplied by the number of primary data points consolidated into it:

row_seconds = profile_step_seconds * archive_steps
retention_seconds = rows * row_seconds
rows = desired_retention_seconds / row_seconds

For three days (259,200 seconds) of one-minute rows, use 4,320 rows. For the same retention at five-minute aggregation, use 864 rows. Round up when the division is not exact. The GUI presents aggregation durations; the stored steps value is their multiplier of the base step, not a count of rows per hour.

Each archive maintains its own data and retention. Older data does not move from one archive into another when the graph timespan changes. Inspect the existing file's step, pdp_per_row and row count with rrdtool info before planning a conversion.

Change existing collection

In released Cacti 1.2.31, Change Profile changes the selected template definitions for future sources; it does not migrate existing local sources. See changing to one-minute collection for a separate, backed-up migration plan and the prepared destination RRD requirement.

Back up the database, configuration and RRD files as a matching recovery set. Record affected sources, their actual file layouts, consolidation functions, retention, ownership and collection schedule. Pause writes while converting files and test the procedure on copies first.

Choose the conversion for the actual change. RRDtool can tune supported fields, resize archives, and, in versions 1.5 and later, add or remove data sources. Changing resolution or rebuilding archives can require a new destination RRD and an explicit data migration. On the main collector, Cacti's cli/splice_rrd.php merges an old file with a prepared destination file; it does not choose the new profile, create a migration plan or recover detail already consolidated away. Consult the selected release's --help and validate the result before replacing a live file.

Deleting every graph is not a prerequisite for a profile migration. The cli/remove_graphs.php --all selection by itself is a dry run; --force performs removal, and eligible data sources are removed by default unless --preserve is supplied. Do not use this operation as a profile-editing shortcut.

For RRDtool operations, see tune, resize, and info. Changing the collector's cron interval is separate from converting its data.

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