Selfhosted

61428 readers

702 users here now

A place to share alternatives to popular online services that can be self-hosted without giving up privacy or locking you into a service you don't control.

Rules:

Detailed Rules Post

Be civil.
No spam.
Posts are to be related to self-hosting.
Don't duplicate the full text of your blog or readme if you're providing a link.
Submission headline should match the article title.
No trolling.
Promotion posts require active participation, with an account that is at least 30 days old. F/LOSS without a paywall has exceptions, with requirements. See the rules link for details. Tags [CBH] or [AIP] are required, see the links in Rule 8 for details.
AI-related discussions and AI-involved promotional posts have additional requirements for tagging, as noted in Rule 7 and the AI & Promotional Post Expanded Rules post, and find example disclosures here.

Resources:

selfh.st Newsletter and index of selfhosted software and apps
awesome-selfhosted software
awesome-sysadmin resources
Self-Hosted Podcast from Jupiter Broadcasting

Any issues on the community? Report it using the report flag.

Questions? DM the mods!

founded 3 years ago

MODERATORS

curbstickle@anarchist.nexus

curbstickle_lw@lemmy.world

Why is my home server using so much RAM for cache + buffer? (lemmy.dbzer0.com)

submitted 2 hours ago by A9nWGzYt@lemmy.dbzer0.com to c/selfhosted@lemmy.world

10 comments fedilink hide all child comments

I have noticed that my home server is strangely using lots of swap (~5 GB), despite having only a few lightweight processes running and loads of RAM installed (32 GB).

Upon configuring Grafana + Prometheus, I noticed a trend where cache + buffer will progressively increase until swap starts to be used. My system and services combined will use ~8 GB RAM. Upon rebooting, the cache + buffer will start anywhere from 3--10 GB, progressively ramp up to ~25 GB in 1--2h, where swap will start to be needed (~3 GB). See the image attached for reference.

My swap filesystem is on an expensive (to me) SSD, and I would like to reduce its wear by as much as possible. I understand that swap can introduce only minimal wear on SSDs depending on its nature and that it can be harmless, but I am still not sure what is causing this behavior (and why) and whether I should worry about it or not. So I figured I should investigate what is happening here.

My main question is, how can I figure out what is causing this behavior? Is it expected? I am looking for guidance from others who are more experienced than me in the topic.

A little bit about my system:

I am running Debian 12 on an NVMe SSD containing the root partition (btrfs) and docker services. I also have two HDDs, one with persistent data (ext4), and the other with backups (ext4). This is majoritarily a single-user machine. I tried using the following kernel parameters, but it hasn't helped:

vm.swappiness=10
vm.vfs_cache_pressure=200

My docker services are:

*arr stack
jellyfin
nextcloud
immich
open-webui + ollama
pi-hole
invidious
romm
nginx proxy manager
grafana + prometheus
other minor services that I don't think are doing much (uptime-kuma, stirlingpdf, vaultwarden, etc)

you are viewing a single comment's thread
view the rest of the comments

[–] irmadlad@lemmy.world 1 points 2 hours ago

Huh....


  System load:  1.26                Temperature:           57.0 C
  Usage of /:   20.4% of 454.86GB   Processes:             527
  Memory usage: 44%                 Users logged in:       1
  Swap usage:   0%                  IPv4 address for eno1: 192.168.1.190

Ubuntu 22.04.5 - 32 GB RAM - 53 total containers

cat /proc/sys/vm/swappiness: 60 (pretty much default)

cat /proc/pressure/cpu: some avg10=0.68 avg60=0.62 avg300=0.67 total=960097774
full avg10=0.00 avg60=0.00 avg300=0.00 total=0
cat /proc/pressure/memory: some avg10=0.00 avg60=0.00 avg300=0.00 total=0
full avg10=0.00 avg60=0.00 avg300=0.00 total=0
cat /proc/pressure/io: some avg10=1.16 avg60=4.88 avg300=3.85 total=2831425045
full avg10=1.11 avg60=4.54 avg300=3.58 total=2653626377