# Reducing memory usage in homelab deployment

**URL:** <https://discuss.prometheus.io/t/reducing-memory-usage-in-homelab-deployment/3285>\
**Category:** General Help/Support\
**Created:** [February 11, 2025, 9:47am UTC](https://discuss.prometheus.io/t/reducing-memory-usage-in-homelab-deployment/3285 "2025-02-11T09:47:32Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Javex](https://avatars.discourse-cdn.com/v4/letter/j/b3f665/32.png) [@Javex](https://discuss.prometheus.io/u/Javex)\
**Post date:** [February 11, 2025, 9:47am UTC](https://discuss.prometheus.io/t/reducing-memory-usage-in-homelab-deployment/3285/1 "2025-02-11T09:47:32Z")

</div>

Hi! I’m using Prometheus in my homelab Kubernetes cluster and I noticed that it has quite high memory usage (~1GB). Yesterday, I spent some time trying to optimise it by deleting metrics I wasn’t using, mostly default Kubernetes ones. I was able to achieve a significant reduction in what “Top 10 series count by metric names” reports (and I also ran `topk(20, count by ( __name__ , job)({ __name__ =~".+"}))` from [here](https://www.robustperception.io/dropping-metrics-at-scrape-time-with-prometheus/)) and then deleted the metrics and even called the tombstone API to ensure it gets cleaned up. This dropped the number of reported series by name quite a bit and I expected to see a reduction in memory usage as a result.

Specifically I added this to my config for both the node & apiserver scraper:

```auto

        metric_relabel_configs:
          # These metrics use a lot of memory and I don't need it
          - source_labels: [__name__]
            regex: 'apiserver_.*'
            action: drop
          - source_labels: [__name__]
            regex: 'etcd_.*'
            action: drop
          - source_labels: [__name__]
            regex: 'scheduler_.*'
            action: drop

```

So today, 24h later I come back to check and Prometheus is using the exact same amount of memory. It reports many fewer time series counts using that query yet memory usage always peaks at up to 1GB. I can’t find any docs on this, it seems almost like Prometheus _aims_ to hit that value:

 ![Screenshot_20250211_200658](https://europe1.discourse-cdn.com/flex017/uploads/prometheus/original/2X/3/3e141c8dba42b55800cc13427ba3b74a84bbf143.png)

Given the size of my setup I would not expect memory requirements that make it the largest container in my small cluster by memory footprint.

What am I doing wrong that prometheus grows so large?

Coincidentally, I’ve set the resource limit to 1Gi for prometheus-server, so I wondered if it reads those values and basically just takes what’s allowed so I reduced that value to 300Mi, but then it would crash the moment Grafana tries to query it for anything.

Any tips?

---

<div class="post-metadata">

**Author:** ![kcrawford](https://avatars.discourse-cdn.com/v4/letter/k/b77776/32.png) [@kcrawford](https://discuss.prometheus.io/u/kcrawford)\
**Post date:** [February 17, 2025, 9:04pm UTC](https://discuss.prometheus.io/t/reducing-memory-usage-in-homelab-deployment/3285/2 "2025-02-17T21:04:55Z")

</div>

Try running:

```auto
ps -eo pmem,pcpu,vsize,pid,cmd | sort -rnk 1 | head

```

to see what processes are using memory and how much.

I have grafana running with prometheus, a python metrics collector for Mikrotik; all in a 1GB LXC container.

```auto
root@grafana:~# ps -eo pmem,pcpu,vsize,pid,cmd | sort -rnk 1 | head
16.6 0.0 323856 48 /lib/systemd/systemd-journald
16.2 0.0 1611920 134 /usr/share/grafana/bin/grafana server --config=/etc/grafana/grafana.ini --pidfile=/run/grafana/grafana-server.pid --packaging=deb cfg:default.paths.logs=/var/log/grafana cfg:default.paths.data=/var/lib/grafana cfg:default.paths.plugins=/var/lib/grafana/plugins cfg:default.paths.provisioning=/etc/grafana/provisioning
14.4 0.0 3536668 137 /usr/local/bin/prometheus --config.file=/etc/prometheus/prometheus-updated.yml --storage.tsdb.retention.time=2y --storage.tsdb.path=/etc/prometheus/data
 5.7 0.0 707204 129 /opt/saltstack/salt/bin/python3.10 /usr/bin/salt-minion MultiMinionProcessManager MinionProcessManager
 2.1 0.0 550012 135 /root/mktxp/bin/python3 /root/mktxp/bin/mktxp export
 1.9 0.0 129176 116 /opt/saltstack/salt/bin/python3.10 /usr/bin/salt-minion
 1.8 0.0 1238884 138 /root/snmp_exporter-0.26.0.linux-amd64/snmp_exporter
 1.8 0.0 106188 119 /usr/bin/python3 /usr/share/unattended-upgrades/unattended-upgrade-shutdown --wait-for-signal
 1.7 0.0 286504 6245 /usr/libexec/packagekitd
 1.3 0.0 32572 283 /root/mktxp/bin/python3 /root/mktxp/bin/mktxp export
root@grafana:~# free -mt
               total used free shared buff/cache available
Mem: 1024 297 27 0 698 726
Swap: 512 19 492
Total: 1536 317 520
root@grafana:~#

```