This sounds like you’ll need to do a balance operation. Try this first and see if it helps:
btrfs balance start -dusage=0 -musage=0 /
If not you can increase the number to 5 or 10. This operation reallocates chunks on the disk and ensures they’re filled - check https://btrfs.readthedocs.io/en/latest/Balance.html for details.
I use HASS.agent to help manage my Windows desktop and expose various sensors to HA. It can suspend or hibernate the system. It does use MQTT as its connectivity plane.
You get easy access to their addons with a VM (aka HAOS). You can do the same thing yourself but you have to do it all (creating the containers, configuring them, figuring out how to connect them to HA/your network/etc., updating them as needed) - whereas with HAOS it generally just works. If you want that control great but go in with that understanding.
BTRFS has RAID built into the file system - instead of using MD you use BTRFS profiles which tell the system how to handle data.
For instance
With this set up you could lose one device (of n, the total doesn’t matter), and not lose any data, and still be able to boot to recover with too much hassle.
BTRFS does block checksums, can scan for bit rot and recover from it, and generally tries to make your data safe. It technically supports raid5/6 for user data, the issue is around unclean shutdowns and a potential write hole where you could lose data, but if your system has a UPS backup and is on a relatively recent kernel it’s not any more dangerous than MD raid5/6 as I understand it.
I’d have to check my iptables syntax again but I’m not sure you want the FORWARD between the networks unless C has a manual route to get traffic for the 192.168.15.0/24 network back via B. You just want to NAT A behind B’s IP on 192.168.38.0/24. I think the forwards are sending the traffic without doing NAT on A.
The phone or browser may be using DNS over HTTP (aka DoH), check if you can disable it for the wifi network. You may have to disable it on the phone or browser to get your desired behaviour - look up directions for your browser.
Right now - easy, with the difficulty going up over time as the main Chromium codebase continues to change (and especially as it gets security updates). I think I’ve read that some variants (Brave?) have committed to supporting ManifestV2 for as long as possible, for instance with their own fork.
If it’s logs, there’s a package called log2ram - it’s designed for small form factor systems to reduce writes to SD cards but does apply anywhere you want to log but not hit disk immediately. It syncs logs to disk on a regular basis so you don’t lose much if the system crashes.
From a Linux command line it would be the command called arp, you need to add a static arp entry. I don’t know how that works on sense, but on Linux it would be something like
arp -s IP MAC
Maybe there’s a module in opnsense to help. The way I’ve done this before is using a machine connected to the same network at my target to wake up by logging into that machine and issuing the wake command.
WoL packets are usually sent to the ip broadcast address for the network as they’re not ip based. I don’t know if this would ever work well across networks. Can you do send the wol packet from the opnsense router instead? Does it work then?
If you’re sending it to the IP of the server, it likely works soon after your turn the machine off because the ARP entry hasn’t timed out yet, but once it times out it won’t work anymore. The router doesn’t know how to get to the machine. You may be able to add a static arp mapping to get it to work long term.
We can’t ever stop this kind of stuff, but with something like fail2ban you can set it up to block on too many failures.
Really though - ensuring your system is kept up to date and uses strong passwords or use a SSH keys is the best defence. Blocking doesn’t prevent them from trying a few times. Moving SSH to a non standard port will stop most of the automated attacks but it won’t stop someone who is dedicated.