[SOLVED} Funny thing with LiveDVD

[turboscrew]

Hi, I'm new to Mageia. I've been test driving a Live DVD (Mageia 4.1).
I've been very busy, and I haven't got time to play with Mageia, so the computer has been idling for a couple of days with LiveDVD Mageia.
Now I tried to check a file on the disk, but the file manager refused to open.
(Something was missing from the desktop.)
The same thing happened with MCC and a couple of other applications.
Firefox just didn't start. It tried for some time (the icon became active and the cursor had the firefox logo hanging besides),
but firefox didn't open.
Also whatever I tried, DVD didn't start - as if the systen had misplaced the disks.
I guess the bug reprting could have worked, but the debugger wasn't installed, so I cancelled.

Any idea what was going on? As if some parts of the system went asleep and couldn't wake up (esp. disks - both DVD and initrd).
Is this known thing with LiveDVD? How about with installed system?
My MoBo is Gigabyte GA-B75M-D3H with i3 processor (integrated HD graphics), if that has something to do with it.

[edit]
Furthermore, should I install the debugger (which, how) and report if that happens again?
If it's not yet a known issue, is there any other pieces of info I could supply?
(I'm embedded programmer, I might manage...)

[benmc]

Hi

is this the same unit that you are also having a problem with the printer?
If so, it symptomatic of a faulty iso or burn.
you may have to re-download your live dvd iso and do a md5 checksum on it.

You could also try

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 urpmi --auto-update

you could also try to rebuild your system rpm database using

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rm -f /var/lib/rpm/__db*
rpm –-rebuilddb

I have had to use this on an HDD install [ Openmandriva lx2014 ] yesterday . I am unsure how it would work with a live system though.

regards

Benmc

addendum:
Given that you are using a live dvd system there is also the possibility of corrupted ram memory in your unit causing problems. remote though.

[turboscrew]

Mageia run fine for the first couple of days. The problem seem to take place after a few days of being idle.
And before the LiveDVD I've run Debian for about year and a half.
And yes, I've been having problems with printer on the same machine.

And I did check the md5sum.

[benmc]

hi

Was your Debian a live disk as well?
How much ram do you have? [ running processes may have been generating logs for errors and may have used up all available ram ]

How about with installed system?

.
I have beeen running Mageia since Mageia1 alpha and have had very few problems, but then I rarely leave my machine running for more than 3 days.

Perhaps you might like to try Mageia in a Virtual Machine [ saves burning a disc and you can continue with your usual O/S ]

[turboscrew]

Was your Debian a live disk as well?

At first (few weeks) a live, afret that installed, until I got fed up with the printer problem.
(I learned that CUPS was older version that had a bug - it wouldn't have worked anyway.)

The las couple of months I've had Mint 17, but the printer doesn't work with that either.
(Freezes at half way of the last page.)

I'm writing this on a Windows laptop with which the printer works fine.

BTW rebooted the Mageia live, and the MCC opens fine again.

[turboscrew]

Now back on Mageia:

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[live@localhost ~]$ free -m
             total       used       free     shared    buffers     cached
Mem:          3831       1977       1853          0        252       1269
-/+ buffers/cache:        454       3376
Swap:            0          0          0


As you see, firefox also works fine.

Also:
[live@localhost ~]$ md5sum /dev/sr0
e9b3369d8f7695f7df69b65932f54a61 /dev/sr0

$ md5sum Mageia-4.1-LiveDVD-KDE4-x86_64-DVD.iso
e9b3369d8f7695f7df69b65932f54a61

Seems to match (the latter was taken from the download page).

[benmc]

run that test again in a few hours and see if your free memory is disappearing

[turboscrew]

I run the md5sum and tried to add printer: got a pop-up:
"No package named system-config-printer"
(forgot to set up the repo.)

Anyway, after these:

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[live@localhost ~]$ free -m
             total       used       free     shared    buffers     cached
Mem:          3831       3662        168          0       1841       1063
-/+ buffers/cache:        757       3073
Swap:            0          0          0


After enabling the repos.

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[live@localhost ~]$ free -m
             total       used       free     shared    buffers     cached
Mem:          3831       3633        197          0       1849       1058
-/+ buffers/cache:        724       3106
Swap:            0          0          0


After setting up canon printer:

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[live@localhost ~]$ free -m
             total       used       free     shared    buffers     cached
Mem:          3831       3501        330          0       1008       1639
-/+ buffers/cache:        852       2978
Swap:            0          0          0


Couple of hours later:

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[live@localhost ~]$ free -m
             total       used       free     shared    buffers     cached
Mem:          3831       3632        199          0        774       1816
-/+ buffers/cache:       1041       2789
Swap:            0          0          0


[jiml8]

My experience has been that over time Mageia will use all available RAM. That which is not needed for applications will be gradually taken over for cache.

This seems to happen more on Mageia than on OpenSUSE (which is the other Linux that I usually have running in a VM). I have never worried about it because I have 32GB of RAM, but sometimes Mageia actually uses some swap, in spite of the large amount of available RAM. It has never caused me any problems so, beyond monitoring it and occasionally freeing some cache, I ignore it. The system is supposed to free cache when the RAM is needed for applications anyway. For reference, I typically have anywhere from 16 to 24 GB in use for my system and for the virtual machines that are running on my system. So there is usually anywhere from 8 to 16 GB available.

In a live distro, where you have no swap, I would speculate that the system potentially could run out of memory because of this. It is supposed to release cache as required, but let us speculate for a second that for some reason it cannot do so, or let us speculate that there is a kernel bug that only manifests in this edge condition. This would give symptoms very much like what you see.

Possibly, on my system, the usage of swap that I see from time to time is related to needing some memory in order to free some cache so that more RAM will be available for applications. I don't know.

In any event, you can test it. When you are out of memory, open a konsole window and enter these commands (as root):

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sync
echo 3 > /proc/sys/vm/drop_caches


then see if your symptoms go away.

[turboscrew]

I better leave a console window open then.
When the problem hit me, I couldn't open a console.

I'm going away for a couple of days, and I'll leave the machine to idle.
I'll see how things are when I'm back.

I'll check that cache-dropping after that.

Thenka.

[turboscrew]

It must have been sone weird "glitch". It didn't happen again.

Now I'm running mageia installed on HD.