Network drops almost daily. Rebooting pi-hole fixes it. What's wrong?

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My pi-hole is, so far as I know, entirely "standard." It's running on an RP4 with 4GB of RAM.

Expected Behaviour:

I expect network access to be stable and consistent.

Actual Behaviour:

The pi-hole has been running for a few months with no issues whatsoever. Then, perhaps a week or so ago, my home network seems to go offline once a day. Sometimes it makes it two days. When this happens, checking the IP address on what is normally a DHCP client shows that it's not receiving a lease. Setting a static IP on the client with DNS pointing at my router brings that client back online. Likewise, rebooting the Pi brings everything back up in about 5 minutes or so.

My suspicion is that this has to do with the pi-hole not serving DCHP leases correctly, not resolving DNS correctly, or some combination of both.

Debug Token:

You are running the Pi on the wlan0 interface, which is not going to be as reliable as using the existing high speed (gigabit on that model) ethernet interface.

*** [ DIAGNOSING ]: Networking
[✓] IPv4 address(es) bound to the wlan0 interface: matches the IP found in /etc/pihole/setupVars.conf

I would check the Pi forums for WiFi connectivity issues (power saving, etc.)

Fair point. I've got it running over WiFi in my office now and had intended to plug it into the router (in another room) once I was certain things were solid. I'll take your recommendation to look into power saving issues; however, this thing was rock solid for a few months and only recently began flaking out, so I'd be interested to hear if anyone has additional suggestions before we call it a day.

Thanks so much.

One thing to check, if the power supply isnt sufficient, "Under-voltage" can occur causing segmentation errors for processes and potentially even corrupt files on the SD card (see link below):

You can check the syslogs for under voltage with below:

sudo zgrep -i voltage /var/log/syslog*

Or check the kernel ring buffer logs:

dmesg -T | grep -i voltage

Or check below one:

pi@phb5:~ $ vcgencmd get_throttled int

Good thoughts.

  • There was a single under voltage alert, from 5 days ago which "normalised" six seconds later.
  • The dmsg command brings back nothing.
  • The vcgencmd command brings back "throttled=0x0" just as you've shown, which seems to indicate that it's not being throttled for under voltage, and never has.

Some extra information, if it helps:

  • Both network monitoring and "uptime" on the Pi indicate that the Pi itself isn't going down during any of these episodes, but rebooting it intentionally does fix the problem. This leads me to think perhaps one of the services is stopping?
  • I don't think it's relevant, but the Pi in question also runs a Plex media server, but the outages have never coincided with Plex use. (i.e. Plex isn't serving any content when the outages happen.)
  • Memory utilization on the Pi never seems to get above 7%.

The last two commands will only show results since last bootup.
The syslogs go back way longer.

Get the rid of the under-voltage messages first by getting a proper power supply or USB cable (see link above) before you can troubleshoot any further.
And maybe filesystem corruption has already occurred so best to start with a fresh SD install again.

EDIT: I'm mistaken, if the host has a long uptime, checking the last two might show results wile the syslogs that get rotated out after 7 days might not.

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Hmm, I've got 4 Pis running off a power source providing 5v, 2.4A to each. It's not the 3A listed as "recommended" in your link but well over the 1.2A listed as "maximum draw." Also, none of the other three Pis have any voltage errors in their syslogs. So I'm not saying this isn't the problem, but it doesn't seem like it should be the problem. Nevertheless, I'll plug the Pi in question into the "approved" cord it came with and proceed from there.

I would like to find a solution that will power all four from a single device as the individual Rp power supplies have rather large "bricks" attached and would require four separate outlets.

Its of no use troubleshooting further without knowing for sure the serious power issues is solved first.
And start with a fresh SD.
Or if you have the possibility, run a fsck on the SD card partitions from another Linux host to check for errors and possibly fix.

Yes, certainly, thank you. I have every intention of doing just that. I was simply sharing what I'm doing now in case it was a "Dear God please don't do that" sort of thing.

Academically though, am I correct that 2.4A should be sufficient, or does everyone really use separate power bricks for each of their Pis?

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Some power adapters are good for charging but not stable enough to power a Pi.
I once run three Pi ones from a USB hub that had a large enough power brick.

Yep, understood, and there were several reviews on the one I bought saying folks were running Pi 4 clusters like a champ. Oh, well, I guess it doesn't matter if it works for them; it needs to work for me.

As I said, I'll plug the Pi in question into its "out of the box" dedicated power supply for now and fsck its SD card. The fresh install is going to be a PITA, but it is what it is.

Thanks so much for the advice.

Maybe something like below or similar can do the job:

Thanks. FWIW, this is the one I have:

I don't use shared power supplies for any Pi's. Each has its own dedicated power brick, independent of the others. And, all on UPS as well.

That's a good charger, by the way. Perhaps a cable swap might be your first step.

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Thats 20 Wats more as the one I suggested :wink:

This is a very reliable power supply of adequate rating.

Yes, thank you - I've got one of those and I'll use it on the Pi in question as soon as I get a chance. (Doing so now would knock me offline and the rest of the "work from home" crowd in the house would likely revolt.)

I was going to ask about UPS. I have one, so I'll plug the Pi into it as well.

So I'll start with swapping out the power supply and connecting a UPS to see if that does the trick. If not, I'll flash the SD card and start from scratch, but I would really like to avoid that if I can.

@deHakkelaar - Yes, that's why I was thinking the power should be sufficient.

You might consider putting all your equipment on the UPS that provides a path to the internet - modem, router, Pi's, switches, hubs, etc. I have a UPS for just this purpose and it will keep me up and running for about 4 hours in case of a power outage. Wireless devices/laptops can continue to use the internet.