# cockroachdb\_underreplicated\_ranges

**URL:** <https://community.netdata.cloud/t/cockroachdb-underreplicated-ranges/2240>\
**Category:** Alerts\
**Created:** [December 2, 2021, 8:18am UTC](https://community.netdata.cloud/t/cockroachdb-underreplicated-ranges/2240 "2021-12-02T08:18:33Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Ancairon](https://yyz1.discourse-cdn.com/flex029/user_avatar/community.netdata.cloud/ancairon/32/1001_2.png) [@Ancairon](https://community.netdata.cloud/u/Ancairon)\
**Post date:** [December 2, 2021, 8:18am UTC](https://community.netdata.cloud/t/cockroachdb-underreplicated-ranges/2240/1 "2021-12-02T08:18:33Z")

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# cockroachdb\_underreplicated\_ranges

## Database | CockroachDB

This alert presents the number of under-replicated ranges.

This alert is raised in a warning state when under-replicated ranges start to exist.

> Under-replicated ranges: When a cluster is first initialized, the few default starting ranges  
> will only have a single replica, but as soon as other nodes are available, they will  
> replicate to them until they’ve reached their desired replication factor. If a range does not  
> have enough replicas, the range is said to be “under-replicated”.
> 
> CockroachDB uses consensus replication and requires a quorum of the replicas to  
> be available in order to allow both writes and reads to the range. The number of failures  
> that can be tolerated is equal to (Replication factor - 1)/2. Thus, CockroachDB requires (n-1)  
> /2 nodes to achieve quorum. For example, with 3x replication, one failure can be tolerated;  
> with 5x replication, two failures, and so on.[1](https://www.cockroachlabs.com/docs/stable/cluster-setup-troubleshooting.html#db-console-shows-under-replicated-unavailable-ranges)

> **References and Sources**
>
> 1. [CockroachDB documentation](https://www.cockroachlabs.com/docs/stable/cluster-setup-troubleshooting.html#db-console-shows-under-replicated-unavailable-ranges)

### Troubleshooting Section

> **Identify under-replicated ranges**
>
> Check out the [CockroachDB documentation](https://www.cockroachlabs.com/docs/stable/cluster-setup-troubleshooting.html#db-console-shows-under-replicated-unavailable-ranges)  
> for troubleshooting advice.