Re: Periodic kernel freezes

[David Goodwin <david@codepoets.co.uk>]

On 30/10/2015 16:25, Alex Adriaanse wrote:
> I have an EC2 instance on AWS that tends to freeze several times per
> week. When it freezes it stops responding to network traffic, disk
> I/O stops, and CPU goes to 100%. The system comes back fine after a
> reboot. I was finally able to get a kernel backtrace from when this
> happened today, which I have attached to this email.
>
> The VM in question runs Debian Jessie, and has 3 BTRFS filesystems,
> including the root filesystem. Details are included below.
>
> Any ideas?
>

Hi Alex -

I kept experiencing problems with the Jessie 3.16.x kernel on EC2 (and 
elsewhere) with BTRFS.

Out of 8 nodes, one managed an uptime of 90 days, while the average was 
about 21 days.

Crashes were seemingly random, and it was difficult to get stack traces.

For the stack traces I did get, it wasn't always obvious that the 
problem lay with BTRFS.

Reboots normally needed to be forceful.

I'd suggest upgrading to a backports kernel (I compiled various 4.1.x 
kernels, but there's now 4.2.x in jessie-backports).

You might also want to turn off compression...

David.