Kiu/VictoriaMetrics
Kiu/VictoriaMetrics
1
0
Fork 0
mirror of https://github.com/VictoriaMetrics/VictoriaMetrics.git synced 2024-12-15 00:13:30 +01:00
Code Issues Actions 1 Packages Projects Releases Wiki Activity

docs/Troubleshooting.md: formatting fixes

Browse Source
This commit is contained in:
Aliaksandr Valialkin 2022-06-30 14:38:42 +03:00
parent 74338ef300
commit 7c54cc2123
No known key found for this signature in database
GPG Key ID: A72BEC6CD3D0DED1
1 changed files with 33 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
docs/Troubleshooting.md
View File

@ -87,46 +87,46 @@ There are the following most commons reasons for slow data ingestion in Victoria
1. Memory shortage for the given amounts of [active time series](https://docs.victoriametrics.com/FAQ.html#what-is-an-active-time-series). 1. Memory shortage for the given amounts of [active time series](https://docs.victoriametrics.com/FAQ.html#what-is-an-active-time-series).
VictoriaMetrics (or `vmstorage` in cluster version of VictoriaMetrics) maintains an in-memory cache VictoriaMetrics (or `vmstorage` in cluster version of VictoriaMetrics) maintains an in-memory cache
for quick search for internal series ids per each incoming metric. for quick search for internal series ids per each incoming metric.
This cache is named `storage/tsid`. VictoriaMetrics automatically determines the maximum size for this cache This cache is named `storage/tsid`. VictoriaMetrics automatically determines the maximum size for this cache
depending on the available memory on the host where VictoriaMetrics (or `vmstorage`) runs. If the cache size isn't enough depending on the available memory on the host where VictoriaMetrics (or `vmstorage`) runs. If the cache size isn't enough
for holding all the entries for active time series, then VictoriaMetrics locates the needed data on disk, for holding all the entries for active time series, then VictoriaMetrics locates the needed data on disk,
unpacks it, re-constructs the missing entry and puts it into the cache. This takes additional CPU time and disk read IO. unpacks it, re-constructs the missing entry and puts it into the cache. This takes additional CPU time and disk read IO.
The [official Grafana dashboards for VictoriaMetrics](https://docs.victoriametrics.com/#monitoring) The [official Grafana dashboards for VictoriaMetrics](https://docs.victoriametrics.com/#monitoring)
contain `Slow inserts` graph, which shows the cache miss percentage for `storage/tsid` cache contain `Slow inserts` graph, which shows the cache miss percentage for `storage/tsid` cache
during data ingestion. If `slow inserts` graph shows values greater than 5% for more than 10 minutes, during data ingestion. If `slow inserts` graph shows values greater than 5% for more than 10 minutes,
then it is likely the current number of [active time series](https://docs.victoriametrics.com/FAQ.html#what-is-an-active-time-series) then it is likely the current number of [active time series](https://docs.victoriametrics.com/FAQ.html#what-is-an-active-time-series)
cannot fit the `storage/tsid` cache. cannot fit the `storage/tsid` cache.
There are the following solutions exist for this issue: There are the following solutions exist for this issue:
- To increase the available memory on the host where VictoriaMetrics runs until `slow inserts` percentage - To increase the available memory on the host where VictoriaMetrics runs until `slow inserts` percentage
will become lower than 5%. If you run VictoriaMetrics cluster, then you need increasing total available will become lower than 5%. If you run VictoriaMetrics cluster, then you need increasing total available
memory at `vmstorage` nodes. This can be done in two ways: either increasing the available memory memory at `vmstorage` nodes. This can be done in two ways: either increasing the available memory
per each existing `vmstorage` node or to add more `vmstorage` nodes to the cluster. per each existing `vmstorage` node or to add more `vmstorage` nodes to the cluster.
- To reduce the number of active time series. The [official Grafana dashboards for VictoriaMetrics](https://docs.victoriametrics.com/#monitoring) - To reduce the number of active time series. The [official Grafana dashboards for VictoriaMetrics](https://docs.victoriametrics.com/#monitoring)
contain a graph showing the number of active time series. Recent versions of VictoriaMetrics contain a graph showing the number of active time series. Recent versions of VictoriaMetrics
provide [cardinality explorer](https://docs.victoriametrics.com/#cardinality-explorer), provide [cardinality explorer](https://docs.victoriametrics.com/#cardinality-explorer),
which can help determining and fixing the source of [high cardinality](https://docs.victoriametrics.com/FAQ.html#what-is-high-cardinality). which can help determining and fixing the source of [high cardinality](https://docs.victoriametrics.com/FAQ.html#what-is-high-cardinality).
2. [High churn rate](https://docs.victoriametrics.com/FAQ.html#what-is-high-churn-rate), 2. [High churn rate](https://docs.victoriametrics.com/FAQ.html#what-is-high-churn-rate),
e.g. when old time series are substituted with new time series at a high rate. e.g. when old time series are substituted with new time series at a high rate.
When VitoriaMetrics encounters a sample for new time series, it needs to register the time series When VitoriaMetrics encounters a sample for new time series, it needs to register the time series
in the internal index (aka `indexdb`), so it can be quickly located on subsequent select queries. in the internal index (aka `indexdb`), so it can be quickly located on subsequent select queries.
The process of registering new time series in the internal index is an order of magnitude slower The process of registering new time series in the internal index is an order of magnitude slower
than the process of adding new sample to already registered time series. than the process of adding new sample to already registered time series.
So VictoriaMetrics may work slower than expected under [high churn rate](https://docs.victoriametrics.com/FAQ.html#what-is-high-churn-rate). So VictoriaMetrics may work slower than expected under [high churn rate](https://docs.victoriametrics.com/FAQ.html#what-is-high-churn-rate).
The [official Grafana dashboards for VictoriaMetrics](https://docs.victoriametrics.com/#monitoring) The [official Grafana dashboards for VictoriaMetrics](https://docs.victoriametrics.com/#monitoring)
provides `Churn rate` graph, which shows the average number of new time series registered provides `Churn rate` graph, which shows the average number of new time series registered
during the last 24 hours. If this number exceeds the number of [active time series](https://docs.victoriametrics.com/FAQ.html#what-is-an-active-time-series), during the last 24 hours. If this number exceeds the number of [active time series](https://docs.victoriametrics.com/FAQ.html#what-is-an-active-time-series),
then you need to identify and fix the source of [high churn rate](https://docs.victoriametrics.com/FAQ.html#what-is-high-churn-rate). then you need to identify and fix the source of [high churn rate](https://docs.victoriametrics.com/FAQ.html#what-is-high-churn-rate).
The most commons source of high churn rate is a label, which frequently change its value. Try avoiding such labels. The most commons source of high churn rate is a label, which frequently change its value. Try avoiding such labels.
The [cardinality explorer](https://docs.victoriametrics.com/#cardinality-explorer) can help identifying The [cardinality explorer](https://docs.victoriametrics.com/#cardinality-explorer) can help identifying
such labels. such labels.
3. Resource shortage. The [official Grafana dashboards for VictoriaMetrics](https://docs.victoriametrics.com/#monitoring) 3. Resource shortage. The [official Grafana dashboards for VictoriaMetrics](https://docs.victoriametrics.com/#monitoring)
contain `resource usage` graphs, which show memory usage, CPU usage, disk IO usage and free disk size. contain `resource usage` graphs, which show memory usage, CPU usage, disk IO usage and free disk size.