This may sound like a vague question so I will provide some context below. The basic question is :

What parameters describe the growth in size of a Prometheus database over time?

To tie the question down: When will the prometheus time series data base reach 1TB if I collect 10 metrics sampling them at 5 per minute?

1 Answer 1


Prometheus use a timeseries databases with vacuum, the documentation gives some maths to plan your disk consumption:

On average, Prometheus uses only around 1-2 bytes per sample. Thus, to plan the capacity of a Prometheus server, you can use the rough formula:

needed_disk_space = retention_time_seconds * ingested_samples_per_second * bytes_per_sample

So depending on your retention configuration, 1TB could never be reach or you can keep a very long time. That said it's using prometheus local storage, using another storage system will change the maths depending on the system concerned, influxdb is one of them and has its own documentation about storage.

  • 1
    oh,now I feel like an idiot. I actually read that page, and totally missed the calculation in it - so thanks! Nov 26, 2018 at 15:10
  • how to get this values retention_time_seconds, ingested_samples_per_second, bytes_per_sample
    – Mark
    Apr 10, 2019 at 4:36
  • @Mark This is values you configure and deduct from your infrastructure.
    – Tensibai
    Apr 10, 2019 at 7:27
  • @Tensibai I think around 200M per hour, then when it reaches 1.1G it will reset to 700M+
    – Mark
    Apr 12, 2019 at 3:28

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