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diff --git a/docs/guides/longer-metrics-storage.md b/docs/guides/longer-metrics-storage.md deleted file mode 100644 index 8ccd9585..00000000 --- a/docs/guides/longer-metrics-storage.md +++ /dev/null @@ -1,158 +0,0 @@ -<!-- -title: "Netdata Longer Metrics Retention" -description: "" -custom_edit_url: https://github.com/netdata/netdata/edit/master/docs/guides/longer-metrics-storage.md ---> - -# Netdata Longer Metrics Retention - -Metrics retention affects 3 parameters on the operation of a Netdata Agent: - -1. The disk space required to store the metrics. -2. The memory the Netdata Agent will require to have that retention available for queries. -3. The CPU resources that will be required to query longer time-frames. - -As retention increases, the resources required to support that retention increase too. - -Since Netdata Agents usually run at the edge, inside production systems, Netdata Agent **parents** should be considered. When having a **parent - child** setup, the child (the Netdata Agent running on a production system) delegates all its functions, including longer metrics retention and querying, to the parent node that can dedicate more resources to this task. A single Netdata Agent parent can centralize multiple children Netdata Agents (dozens, hundreds, or even thousands depending on its available resources). - - -## Ephemerality of metrics - -The ephemerality of metrics plays an important role in retention. In environments where metrics stop being collected and new metrics are constantly being generated, we are interested about 2 parameters: - -1. The **expected concurrent number of metrics** as an average for the lifetime of the database. - This affects mainly the storage requirements. - -2. The **expected total number of unique metrics** for the lifetime of the database. - This affects mainly the memory requirements for having all these metrics indexed and available to be queried. - -## Granularity of metrics - -The granularity of metrics (the frequency they are collected and stored, i.e. their resolution) is significantly affecting retention. - -Lowering the granularity from per second to every two seconds, will double their retention and half the CPU requirements of the Netdata Agent, without affecting disk space or memory requirements. - -## Which database mode to use - -Netdata Agents support multiple database modes. - -The default mode `[db].mode = dbengine` has been designed to scale for longer retentions. - -The other available database modes are designed to minimize resource utilization and should usually be considered on **parent - child** setups at the children side. - -So, - -* On a single node setup, use `[db].mode = dbengine` to increase retention. -* On a **parent - child** setup, use `[db].mode = dbengine` on the parent to increase retention and a more resource efficient mode (like `save`, `ram` or `none`) for the child to minimize resources utilization. - -To use `dbengine`, set this in `netdata.conf` (it is the default): - -``` -[db] - mode = dbengine -``` - -## Tiering - -`dbengine` supports tiering. Tiering allows having up to 3 versions of the data: - -1. Tier 0 is the high resolution data. -2. Tier 1 is the first tier that samples data every 60 data collections of Tier 0. -3. Tier 2 is the second tier that samples data every 3600 data collections of Tier 0 (60 of Tier 1). - -To enable tiering set `[db].storage tiers` in `netdata.conf` (the default is 1, to enable only Tier 0): - -``` -[db] - mode = dbengine - storage tiers = 3 -``` - -## Disk space requirements - -Netdata Agents require about 1 bytes on disk per database point on Tier 0 and 4 times more on higher tiers (Tier 1 and 2). They require 4 times more storage per point compared to Tier 0, because for every point higher tiers store `min`, `max`, `sum`, `count` and `anomaly rate` (the values are 5, but they require 4 times the storage because `count` and `anomaly rate` are 16-bit integers). The `average` is calculated on the fly at query time using `sum / count`. - -### Tier 0 - per second for a week - -For 2000 metrics, collected every second and retained for a week, Tier 0 needs: 1 byte x 2000 metrics x 3600 secs per hour x 24 hours per day x 7 days per week = 1100MB. - -The setting to control this is in `netdata.conf`: - -``` -[db] - mode = dbengine - - # per second data collection - update every = 1 - - # enable only Tier 0 - storage tiers = 1 - - # Tier 0, per second data for a week - dbengine multihost disk space MB = 1100 -``` - -By setting it to `1100` and restarting the Netdata Agent, this node will start maintaining about a week of data. But pay attention to the number of metrics. If you have more than 2000 metrics on a node, or you need more that a week of high resolution metrics, you may need to adjust this setting accordingly. - -### Tier 1 - per minute for a month - -Tier 1 is by default sampling the data every 60 points of Tier 0. If Tier 0 is per second, then Tier 1 is per minute. - -Tier 1 needs 4 times more storage per point compared to Tier 0. So, for 2000 metrics, with per minute resolution, retained for a month, Tier 1 needs: 4 bytes x 2000 metrics x 60 minutes per hour x 24 hours per day x 30 days per month = 330MB. - -Do this in `netdata.conf`: - -``` -[db] - mode = dbengine - - # per second data collection - update every = 1 - - # enable only Tier 0 and Tier 1 - storage tiers = 2 - - # Tier 0, per second data for a week - dbengine multihost disk space MB = 1100 - - # Tier 1, per minute data for a month - dbengine tier 1 multihost disk space MB = 330 -``` - -Once `netdata.conf` is edited, the Netdata Agent needs to be restarted for the changes to take effect. - -### Tier 2 - per hour for a year - -Tier 2 is by default sampling data every 3600 points of Tier 0 (60 of Tier 1). If Tier 0 is per second, then Tier 2 is per hour. - -The storage requirements are the same to Tier 1. - -For 2000 metrics, with per hour resolution, retained for a year, Tier 2 needs: 4 bytes x 2000 metrics x 24 hours per day x 365 days per year = 67MB. - -Do this in `netdata.conf`: - -``` -[db] - mode = dbengine - - # per second data collection - update every = 1 - - # enable only Tier 0 and Tier 1 - storage tiers = 3 - - # Tier 0, per second data for a week - dbengine multihost disk space MB = 1100 - - # Tier 1, per minute data for a month - dbengine tier 1 multihost disk space MB = 330 - - # Tier 2, per hour data for a year - dbengine tier 2 multihost disk space MB = 67 -``` - -Once `netdata.conf` is edited, the Netdata Agent needs to be restarted for the changes to take effect. - - - |