Something happened to my R5F27 box recently. Seems as though my mythbackend is really messed-up.

Symptoms: Can't connect to backend on the local box
Mythweb doesn't function

Here is the relevent section of my /var/log/mythtv/mythbackend.log:



It goes on to give lines like:


The IP addy of this machine is indeed 192.168.0.4. Here is a screenshot of mythtv-setup's config page which I believe to be the right configuration since I'm running other boxes as frontends to need to connect to this backend:



I followed cesman's repairing mysql tables instructions but found that I had no errors.

I also forced an fsck but no errors were detected after the reboot.



After searching a bit, it seems that this "No error type from QSqlError? Strange..." could be due to the old skip-networking line in /etc/mysql/my.cnf but that has been replaced as you know by the bind-address line which is required if one is using other frontend machines which I am. Therefore my /etc/mysql/my.cnf does contain the following line:


Just for testing purposes, I did comment it out and restarted mysql but the same problem exists. I'm currently unable to connect to my own backend machine.

Suggestions are welcomed

_________________
Retired KM user (R4 - R6.04); friend to LH users.

A couple of questions:

* is it only the remote frontends that can't connect? In other words, does running the frontend on the backend machine work?

* are you confident that ALL your remote frontends are running the same version of MythTV? It should warn you if your versions are out of sync, but a newer version can also update an older version and get the database all screwed up.

No, I can't get the local machine to connect via it's frontend nor can I connect to it via mythweb. I haven't even fired out one of the remote frontend machines at all since the local frontend can't connect. So the answer to you question is: the frontend on the beckend machine doesn't connect

To answer your second bullet point: I am 100 % sure that ALL my remote frontends are running the same version. I've had them setup like this for years without problems. Again, I haven't tried one of the remote frontends since the box's frontend cannot connect to its own backend.

_________________
Retired KM user (R4 - R6.04); friend to LH users.

Is MySQL actually running? See this for troubleshooting ideas.

Yeah, been quite the rash of these lately. Any Ubuntu-based frontends in your mix?

no Ubuntu-based frontends... all machines are KM R5F27. But, again, the backend machine sits in my living room and we also use it to watch programs via the frontend that has been able to connect to the backend (both on the same box).

Yeah, it's running...:

_________________
Retired KM user (R4 - R6.04); friend to LH users.

If I open an xterm and try to run mythfronend while logging the output, I get the following. By the way, it take about 60-90 seconds before I see the mythfronend GUI. In the past, it runs very quickly (3-4 sec):

_________________
Retired KM user (R4 - R6.04); friend to LH users.

Do /var/log/mysql.log or /var/log/mysql.err provide any clues? And what processes do you see running with ps -ef | grep -i sql?

Please post a copy of the /etc/my.cnf
could be that mysql is only listening on the unix socket (/var/run/mysqld/mysqld.sock) but not on tcpip port 3306.
you should have an entry under "mysqld" section that says:

Please advise. This would make it so you couldnt connect even locally via myth (since it assumes ip based connectivity instead of local socket) yet mysql would be running.

_________________
"If the facts don't fit the theory, change the facts"
--Albert Einstein

Well, it just started working without my intervention. I left the box up and did some yard work. When I came back everything was as it should be. I just power cycled the box and the frontend came up all by itself; as well, I can connect to mythweb again.

Too spooky!

Thanks to all who replied.

_________________
Retired KM user (R4 - R6.04); friend to LH users.

Odd, it did this behavior AGAIN today (no reason that I can tell). After leaving it to sit for about 45 min, it was fine. Again, I forced an fsck and also looked for corruption of my mysql tables. Both tests were negative.

I will gladly post any log file. I'd like to figure out what's going on

_________________
Retired KM user (R4 - R6.04); friend to LH users.

Heat related flakeyness? Did it finally start running in the evening after
failing to run during the day? Blow all the dust out of it and see if the
problem goes away.

Out of disk space on root or on myth?

Cliff

Not heat related after checking my system monitors. It finally started working after 45 min or so and a reboot. I also have plenty of disk space.

??

_________________
Retired KM user (R4 - R6.04); friend to LH users.

Could this problem be a symptom of some sort of recovery feature in mysql or something else? We just lost power and I switched the mythtv box on and it's doing it again!

_________________
Retired KM user (R4 - R6.04); friend to LH users.

I could be completely off base here, but could it be a network problem? How is the combined FE/BE connected to the network (wired or WiFi).

I noticed this in the snippet you posted.

That implies to me that your local front end is trying to go out to the network, and then back into the machine via its IP address. If there was a network adaptor, cabling, or router problem, it would make perfect sense that the FE couldn't connect to the BE via that IP routing.

The flakiness of it worked, then it didn't, then it did again ... If one of the above components was failing, it could work intermittently. If a network cable wasn't quite seated properly, minor temperature difference, subtle vibration, or a pet walking behind the Myth box (or router) could cause that. A bit of corrosion on the network cable connectors would do the same. A WiFi connection could be subject to some new bit of interference, such as a neighbour with a new router on the same channel as yours.

Is it possible that your router is assigning a new/different IP address to your Knoppmyth box? I don't know how Myth responds to a dynamic IP address. Is the backend fixed to the one set during "mythtv-setup," or under newer releases does that get re-assigned to the IP address of its machine when re-booted?

I've always set all my machines address in the router via their MAC address. I've seen lots of cases where things stop working when the router is left to decide IP addresses on its own. Machines booted in a different order may get different IP addresses that they used to have. That's caused network printers to not print, bittorrents to stop working, webcam chats to no longer get routed to the right machine ... I know a preparer who couldn't access tax returns on his own machine when a network card went bad, because the configuration pointed to the returns as if they were across the network.

I thought the connection via the machine's IP address looked odd. I know that in UTILITIES/SETUP | SETUP | GENERAL | DATABASE SERVER SETTINGS, it references "localhost". I always thought that "localhost" referred to the reserved IP address of 127.0.0.1! I notice my R5.5 release candidate version is setup that way (via the machine's actual IP address, not the standard 127.0.0.1).

I just check an older, smaller, archived hard drive (read that as "sitting on a shelf in the corner of the room"), that had R5F1 on it. It does use the 127 address for the Master Backend, as I thought I had remembered. I don't have another drive with F27 on it, but I might do a temp install if it just to see what it uses. Or perhaps someone else with an F27 install can check the MBE IP address in myth-setup.



Like I said, I could just be making gaseous emissions through the wrong orifice. I'm knowledgeable enough to understand the concepts, but not Linux skilled enough to make valuable contributions to the project. But the problem you described seems to fit with some of what I've postulated above.