Another possible hypothesis, for why my server-box sometimes crashes.

I have written before, that my Linux computer ‘Phoenix’, which acts both as my server and a workstation, sometimes crashes. I have another possible explanation for why.

The graphics chip on this machine is only a , capable of OpenGL 2.1.2 using proprietary (legacy) drivers. It only has 128MB of shared memory with my motherboard.

Under Windows 10, this chipset is no longer supported at all.

I may simply be pushing this old GPU too hard.

My display is a 1600×1200 monitor, and much of the graphics memory is simply being taken up by that fact. Also, I have many forms of desktop compositing switched on. And at the time of the last crash, I had numerous applications open at the same time, which use hardware 2D acceleration as part of their canvas. And I was copying and pasting between them.

I am hoping that this is easing the burden on my equally-dated CPU.

But then the triggering factor may simply be an eventual error in the GPU.

The fact that the Timeout Detection and Recovery (‘TDR’) does not kick in to save the session, may be due to the possibility that the TDR only works, in specific situations, such as OpenGL, 3D rendering windows. If the GPU crash happens as part of the compositing, it may take out the X-server, and therefore my whole system.

The only workaround I may have, is to avoid using this box as a workstation. When I avoid doing that, it has been known to run for 60 days straight, without crashing…

Dirk

(Edit 01/28/2017 : )

I use a widget on my desktops, which is named ‘‘, and I find that it gives me a good intuitive grasp of what is happening on my Linux computers.


 

phoenix_temperatures_1


 

This widget has as a disadvantage, that when extensions have been installed to display temperatures, sometimes we do not know which temperature-sensors stand for which temperature. This is due to the fact that Linux developers have to design their software, without any knowledge of the specific hardware it is going to run on. Inversely, the makers of proprietary drivers know exactly which machine those are going to run on, and can therefore identify what each of them stands for.

This also means, sometimes we have temperature readings in ‘‘, which may just be spurious, and which may just constantly display one meaningless number, in which case we reduce our selection of indicated temperatures to ones we can identify.

In the context of answering my own question, another detail which becomes relevant, is the fact that this tower computer has a failed case-fan, which is accurately being indicated as the ‘‘ entry, running at 46 RPM at the moment of the screen-shot. I know that this case-fan is in fact stalled, from past occasions when I opened up the tower.

Continue reading Another possible hypothesis, for why my server-box sometimes crashes.

I do not own my own router.

One thing which exists in a big way in Canada, is that ISP subscribers own their own router. But as it happens, my router is owned by Bell and rented to me. The official reason for this, is the fact that my router also provides me with Bell Fibe TV, which contrarily to the naming, is in fact provided over IP via DSL twisted-pair wires.

This paid-for TV content is DRM, so that it is hard to imagine that any other computer enthusiasts have managed to set up their own router, and to receive Fibe TV anyway.

But this also means that I do not have the access to flash my own router. Bell can flash the router when they see a need, but I cannot. And this also means that I cannot obtain full control over this router.

Readers might think that this is an odd situation, for a person who sets up a Web-server, and an OpenVPN-server, at his home IP address. But by using IP-tables in my Linux configuration, I have been able to do precisely that. In particular, the OpenVPN-server requires an ‘IP Masquerade’ to work. But as of my last test, it does work.

But because I am a person who ‘sometimes thinks suspiciously’, I have also had ideas, about what other consequences might arise, from the router being under the control of somebody else. One thing which may happen, is that this router, which displays no options or information regarding IPv6, may get confused and start dropping clients, over repeated requests for IPv6 addresses.

The Web-interface of this router is a dumbed-down interface, which I can access, but which for my benefit, does not give me deep control over the settings. One thing which remains true however, is that in Canada, there is next to no real use of IPv6 from the side of ISPs.

Now, I have set up an IPv6 gateway, which allows my site to be fetched by way of IPv6 if this is desired. But I have also set up my ‘ip6tables‘ in such a way that any request my Server makes for an IPv6 address, gets routed to this gateway, and not to my physical Ethernet connection. It is only logical. So ‘ping6‘ works gloriously on the Server, but not on my laptop. When I do a ‘ping6‘ on my server-box, I also get to see a graphical display in my ‘gkrellm‘ monitor widget, of activity going out over my ‘teredo‘ virtual NIC, not over my real NIC.

And so I have a somewhat lopsided configuration at home, but one which does what I want it to do.

Dirk