a_fancy_kiwi

I recently noticed that htop displays a much lower 'memory in use' number than free -h, top, or fastfetch on my Ubuntu 25.04 server.

I am using ZFS on this server and I've read that ZFS will use a lot of RAM. I also read a forum where someone commented that htop doesn't show caching used by the kernel but I'm not sure how to confirm ZFS is what's causing the discrepancy.

I'm also running a bunch of docker containers and am concerned about stability since I don't know what number I should be looking at. I either have a usable ~22GB of available memory left, ~4GB, or ~1GB depending on what tool I'm using. Is htop the better metric to use when my concern is available memory for new docker containers or are the other tools better?

Server Memory Usage:

• htop = 8.35G / 30.6G
• free -h =

               total        used        free      shared  buff/cache   available
Mem:            30Gi        26Gi       1.3Gi       730Mi       4.2Gi       4.0Gi

• top = MiB Mem : 31317.8 total, 1241.8 free, 27297.2 used, 4355.9 buff/cache
• fastfetch = 26.54GiB / 30.6GiB

EDIT:

Answer

My Results

tldr: all the tools are showing correct numbers. Htop seems to be ignoring ZFS cache. For the purposes of ensuring there is enough RAM for more docker containers in the future, htop seems to be the tool that shows the most useful number with my setup.

This is a continuation of my other post

I now have homeassistant, immich, and authentik docker containers exposed to the open internet. Homeassistant has built in 2FA and authentik is being used as the authentication for immich which supports 2FA. I went ahead and blocked connections from every country except for my own via cloudlfare (I'm aware this does almost nothing but I feel better about it).

At the moment, if my machine became compromised, I wouldn't know. How do I monitor these docker containers? What's a good way to block IPs based on failed login attempts? Is there a tool that could alert me if my machine was compromised? Any recommendations?

EDIT: Oh, and if you have any recommendations for settings I should change in the cloudflare dashboard, that would be great too; there's a ton of options in there and a lot of them are defaulted to "off"

tldr: I'd like to set up a reverse proxy with a domain and an SSL cert so my partner and I can access a few selfhosted services on the internet but I'm not sure what the best/safest way to do it is. Asking my partner to use tailscale or wireguard is asking too much unfortunately. I was curious to know what you all recommend.

I have some services running on my LAN that I currently access via tailscale. Some of these services would see some benefit from being accessible on the internet (ex. Immich sharing via a link, switching over from Plex to Jellyfin without requiring my family to learn how to use a VPN, homeassistant voice stuff, etc.) but I'm kind of unsure what the best approach is. Hosting services on the internet has risk and I'd like to reduce that risk as much as possible.

1. I know a reverse proxy would be beneficial here so I can put all the services on one box and access them via subdomains but where should I host that proxy? On my LAN using a dynamic DNS service? In the cloud? If in the cloud, should I avoid a plan where you share cpu resources with other users and get a dedicated box?

2. Should I purchase a memorable domain or a domain with a random string of characters so no one could reasonably guess it? Does it matter?

3. What's the best way to geo-restrict access? Fail2ban? Realistically, the only people that I might give access to live within a couple hundred miles of me.

4. Any other tips or info you care to share would be greatly appreciated.

5. Feel free to talk me out of it as well.

EDIT:

If anyone comes across this and is interested, this is what I ended up going with. It took an evening to set all this up and was surprisingly easy.

• domain from namecheap
• cloudflare to handle DNS
• Nginx Proxy Manager for reverse proxy (seemed easier than Traefik and I didn't get around to looking at Caddy)
• Cloudflare-ddns docker container to update my A records in cloudflare
• authentik for 2 factor authentication on my immich server

I've been interested in building a DIY NAS out of an SBC for a while now. Not as my main NAS but as a backup I can store offsite at a friend or relative's house. I know any old x86 box will probably do better, this project is just for the fun of it.

The Orange Pi 5 looks pretty decent with its RK3588 chip and M.2 PCIe 3.0 x4 connector. I've seen some adapters that can turn that M.2 slot into a few SATA ports or even a full x16 slot which might let me use an HBA.

Anyway, my question is, assuming the CPU isn't a bottle neck, how do I figure out what kind of throughput this setup could theoretically give me?

After a few google searches:

• PCIe Gen 3 x4 should give me 4 GB/s throughput
• that M.2 to SATA adapter claims 6 ~~GB/s~~ Gb/s throughput
• a single 7200rpm hard drive should give about 80-160MB/s throughput

My guess is that ultimately, I'm limited by that 4GB/s throughput on the PCIe Gen 3 x4 slot but since I'm using hard drives, I'd never get close to saturating that bandwidth. Even if I was using 4 hard drives in a RAID 0 config (which I wouldn't do), I still wouldn't come close. Am I understanding that correctly; is it really that simple?