Bcache can’t differentiate between data and metadata on the cache drive (it’s block level caching), so if something happens to a write-back cache device you lose data, and possibly the entire array. I wouldn’t use bcache (or zfs caching) without mirrored devices personally to ensure resiliency of the array. I don’t know if zfs is smarter - presumably is can be because it’s in control of the raw disks, I just didn’t want to deal with modules.
For your second scenario - yes you can use md under bcache with no issues. It becomes more to configure but once set up has been solid. I actually do md/raid1 - luks - bcache - btrfs layers for the SSD cache disks, where the data drives just use luks - bcache - btrfs. Keep in mind that with bcache if you lose a cache disk you can’t mount - and of course if you’re doing write-back caching then the array is also lost. With write-through caching you can force disconnect the cache disk and mount the disks.
There’s your answer: you need an active PoE injector that follows 802.3af. None of the ones you pictured are the correct ones, they are passive not active and worst case can damage your device.
The difference is the active injector and the device communicate to determine how much power to provide, where the passive injectors just whack the device with their rated power. The device shouldn’t work without negotiation (per the spec).
Based on what I’ve seen with my use of ZRam I don’t think it reserves the total space, but instead consumes whatever is shown in the output of zramctl --output-all. If you’re swapping then yes it would take memory from the system (up to the 8G disk size), based on how compressible the swapped content is (like if you’re getting a 3x ratio it’s 8GB/3=2.6GB). That said - it will take memory from the disk cache if you’re swapping.
Realistically I think your issue is IO and there’s not much you can do with if your disk cache is being flushed. Switching to zswap might help as it should spill more into disk if you’re under memory pressure.
Check with your provider for SIP server, username and password, and if they have a suggested app (even if you don’t want to use it, it means they have some kind of support). It’s probably in their support pages somewhere.
You don’t need cards to have full bandwidth, they only time it will matter is when you’re loading the models on the card. You need a motherboard with x16 slots but even x4 connections would be good enough. Running the model doesn’t need a lot of bandwidth. Remember you only load the model once then reuse it.
An x4 pcie gen 4 slot has ~7.8 GiB/s theoretical transfer rate (after overhead), a x16 has ~31.5GiB/s - so disk I/O is likely your limit even for a x4 slot.
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.
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.
Without looking at it it’s probably making a unique request to a resource on a NextDNS subdomain and watching where the request comes from. Like pulling an image from (unique _string).check.nextdns.com. This requires nothing special on the client, it’s making a standard request, and as part of that it needs to do a DNS lookup.
If the source of the and your IP are similar then it’s likely the same network, otherwise it can correlate the source with known resolvers.
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.
Yes I simplified. Some(? I’d hope all but probably not) new fobs do turn off (ignore the car broadcast) if they are not moved for a time. I proved this to myself with my 2020 car by putting my keys down by my car door, I could only unlock the car for a minute or two after I put it down, after that keyless entry didn’t work until I disturbed the fob to wake it up.
This is to mitigate the relay attack at home (and I’m sure other times, like if the key is in a purse), one avenue was that attackers would count on people hanging their keys by the door, so accessible to selective standing on the stoop with a relay. By turning off at rest they can’t be exploited this way.
Older fobs never turned off - so they are constantly broadcasting the signal for the car. Newer fobs do turn off when at rest so they’re less risky, but if say it’s in your pocket it’s constantly moving so someone could still relay it to steal your vehicle, assuming they get close enough to you.
The faraday bag is good for older fobs or if you think you’re at risk of a key relay attack.
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.
Not sure what you mean by this - Nabu Casa has a Zwave device already called ZWA-2 which is fully supported.