﻿---
title: Migrating from Rollup to downsampling
description: Rollup and downsampling are two different features that allow historical metrics to be rolled up. From a high level rollup is more flexible compared to...
url: https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/4251/manage-data/lifecycle/rollup/migrating-from-rollup-to-downsampling
products:
  - Elasticsearch
---

# Migrating from Rollup to downsampling
Rollup and downsampling are two different features that allow historical metrics to be rolled up. From a high level rollup is more flexible compared to downsampling, but downsampling is a more robust and easier feature to downsample metrics.
The following aspects of downsampling are easier or more robust:
- No need to schedule jobs. Downsampling is integrated with Index Lifecycle Management (ILM) and Data Stream Lifecycle (DSL).
- No separate search API. Downsampled indices can be accessed using the search API and ES|QL.
- No separate rollup configuration. Downsampling uses the time series dimension and metric configuration from the mapping.

It isn’t possible to migrate all rollup usages to downsampling. The main requirement is that the data should be stored in Elasticsearch as [time series data stream (TSDS)](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/4251/manage-data/data-store/data-streams/time-series-data-stream-tsds). Rollup usages that basically roll the data up by time and all dimensions can migrate to downsampling.
An example rollup usage that can be migrated to downsampling:
```json

{
  "index_pattern": "sensor-*",
  "rollup_index": "sensor_rollup",
  "cron": "0 0 * * * *",
  "page_size": 1000,
  "groups": {
    "date_histogram": {
      "field": "timestamp",
      "fixed_interval": "60m"
    },
    "terms": {
      "fields": [ "node" ]
    }
  },
  "metrics": [
    {
      "field": "temperature",
      "metrics": [ "min", "max", "sum" ]
    },
    {
      "field": "voltage",
      "metrics": [ "avg" ]
    }
  ]
}
```

The equivalent [time series data stream (TSDS)](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/4251/manage-data/data-store/data-streams/time-series-data-stream-tsds) setup that uses downsampling using DSL:
```json

{
  "index_patterns": ["sensor-*"],
  "data_stream": { },
  "template": {
    "lifecycle": {
        "downsampling": [
            {
                "after": "1d", <1>
                "fixed_interval": "1h" <3>
            }
        ]
    },
    "settings": {
      "index.mode": "time_series"
    },
    "mappings": {
      "properties": {
        "node": {
          "type": "keyword",
          "time_series_dimension": true <2>
        },
        "temperature": {
          "type": "half_float",
          "time_series_metric": "gauge" <4>
        },
        "voltage": {
          "type": "half_float",
          "time_series_metric": "gauge" <4>
        },
        "@timestamp": { <2>
          "type": "date"
        }
      }
    }
  }
}
```