On 06/11/2015 07:33 AM, Tomasz Chmielewski wrote: > I have a server where I've installed a couple of LXC guests, btrfs - so > easy to test things with snapshots. Or so it seems. > > Unfortunately the box crashes when I put "too much IO load" - with too > much load being these two running at the same time: > > - quite busy MySQL database (doing up to 100% IO wait when running alone) > - busy mongo database (doing up to 100% IO wait when running alone) > > With both mongo and mysql running at the same time, it crashes after 1-2 > days (tried kernels 4.0.4, 4.0.5, 4.1-rc7 from Ubuntu "kernel-ppa"). It > does not crash if I only run mongo, or only mysql. There is plenty of > memory available (just around 2-4 GB used out of 32 GB) when it crashes. > > As the box is only reachable remotely, I'm not able to catch a crash. > Sometimes, I'm able to get a bit of it printed via remote SSH, like here: > > [162276.341030] BUG: unable to handle kernel NULL pointer dereference at > 0000000000000008 The 0x8 part is identical to your chattr +C crash, so its safe to assume that we can focus on that on. I'll see what I can find, but if you can run with CONFIG_DEBUG_PAGEALLOC (it'll be slow) my guess is the suspect will pop out pretty quickly. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
