FreeBSD 10.1 crashing under load

[Fabian Keil]

Christian Kujau <lists at nerdbynature.de> wrote:

> I have a Lenovo Ideapad S10 netbook running FreeBSD 10.1-p5 and 
> ever since I switched from Linux Fedora to FreeBSD the system crashes 
> regularly when the system is under a bit of load :-\
> 
> This netbook is operated in a headless mode, so I'm not using Wifi, 
> Bluetooth or other fancy hardware features this netbook might have, only 
> the system's disk and ethernet.
> 
> I've put a few more details below, but what I wanted to ask is: are there 
> any flags to set in FreeBSD so that it's more chatty when it crashes? 

Using a kernel with WITNESS and INVARIANTS sometimes results in
the problem being caught earlier.

> Right now the system just reboots but leaves nothing in the system log as 
> to _why_ it crashed. I've configured a crash dump device as per [0] but no 
> crash dump is ever taken. I'm running with encrypted swap (via GELI), 
> maybe crashdumping doesn't work with encrypted swap?

IIRC it's not officially supported but you can dump on the device
below the geli layer:

fk at r500 ~ $swapinfo 
Device          1K-blocks     Used    Avail Capacity
/dev/ada0s1b.eli   2097152        0  2097152     0%
fk at r500 ~ $dumpon -l
ada0s1b

Saving the dump automatically after boot doesn't work (for me),
but "service savecore start" works after "swapoff -a".

Obviously such a configuration is not without risks, especially
if you forget to overwrite the dump dev after saving the core.

> When running, this spawns some ~40 java processes that can be quite
> active on both CPU and network & disk I/O. It uses a lot of memory too
> and the machine does only have 1GB of physical memory (+1GB swap) but even
> if the application would use too much memory I'd expect the application to
> crash, not the whole system. The following is from "top -b" right before
> the machine crashed:

Maybe you need to play with vm.overcommit for details see tuning(7).

Fabian
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