[mythtv-users] Please help me move my backend to new host/hardware.

Ram Ramesh rramesh2400 at gmail.com
Sun Mar 26 21:33:50 UTC 2023


On 3/26/23 11:21, Ram Ramesh wrote:
> On 3/25/23 22:08, Stephen Worthington wrote:
>>
>> To diagnose shut down and power off problems, you could enable a
>> systemd early debug shell:
>>
>> https://freedesktop.org/wiki/Software/systemd/Debugging
>>
>> Early debug shells also linger around late during shut down, so you
>> can do Ctrl-Alt-F9 and do commands like "systemctl list-jobs" and
>> "systemctl list-jobs | grep running" to see what is going on and what
>> is holding up the shut down.  My usual culprits are SMB mounts that
>> are still trying to connect to a VM that was running on the same PC
>> and has already been shut down.
>>
>> Systemd will also often post messages about what it is waiting for,
>> which should show on the console after the GUI shuts down.
>>
>> Having a zombie process waiting for some combination of events that is
>> never going to happen before it will shut down is another common
>> culprit - network problems are the usual cause of these for me, with
>> the program in question trying to access a remote file it can not see
>> any more.  This will cause a long delay, but not ultimately prevent a
>> shut down.  It is best to wait at least 10 minutes before using the
>> reset or power button, to see if it will eventually shut down, and
>> hopefully allow it to log something about what happened.
>>
>> And if you are having to use the power or reset button, it is a good
>> idea to enable all the SysRq keystrokes, so you can do Alt-SyqRq
>> REISUB to shut down the filesystems safely before forcing a reboot.
>> That prevents the usual filesystem corruption you get when using reset
>> or the power button while the filesystems are still up.
>>
>> https://linuxconfig.org/how-to-enable-all-sysrq-functions-on-linux
>>
>> On Ubuntu, I have this towards the end of my /etc/sysctl.conf file:
>>
>> ###################################################################
>> # Magic system request Key
>> # 0=disable, 1=enable all, >1 bitmask of sysrq functions
>> # Seehttps://www.kernel.org/doc/html/latest/admin-guide/sysrq.html
>> # for what other values do
>> #kernel.sysrq=438
>> kernel.sysrq=1
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> Thanks for the guidance. Like I said, shutdown (on the new machine 
> with old system kernel copied over) was working just  fine until I 
> added sas 9211 hba card and a couple disks that were on my old system. 
> Now it completes every step and comes to reboot target and then 
> reports that some one is trying to do some extra work that kernel is 
> ignoring. I will get the exact message and post it here. I am almost 
> sure that if I take out the hba card, everything will work fine. 
> However, I do not have enough SATA ports that I need this card. 
> Apparently, this is one of the cards that has excellent (long time) 
> support on the linux side. Since my backend is always on machine, I am 
> not too inconvenienced by this limitation as of now. Still it bothers 
> me that I have to push the power button and hold it to force the 
> situation.
>
>   I will try to post on one of the kernel threads or debian-user to 
> see what I get. I doubt there are any filesys corruption issues 
> because on screen log shows everything except actual power off or 
> reboot is done. So, I am less worried about pushing the power button.  
> However, I will try all of your above suggestions and will learn what 
> internal system state is and go from there.
>
> Regards
> Ramesh

Here is what the screen says when it goes into an infinite loop 
reporting some event and stays there (I only waited 5 min)

    [OK] Reached tagget Power-off
    [67652.NNNNNN] block device autoloading is deprecated and will be
    removed
    <repeat 9 more times with different numbers for NNNN>
    [67667.NNNNNN] blkdev_get_no_open: 119 callbacks suppressed
    <messge repeats endlessly from block device autoloading line with
    different NNNN>

I assume by "[OK]..."  line that we are really at the end of shut down 
process. When I turn off and reboot, no fsck messages. So, I assume that 
filesystems are safe and kernel is somehow lost in some thread.

Regards
Ramesh


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