Comment 34 for bug 666211

on individual devices

i changed the app running on my machine, and at some point i might
also have reinstalled, tho the problem was previously also present
after a previous reinstall

i think the barrier stuff is the conclusion i came ot after reading
source, and i think without further testing it is the reason i'm
stable now

On Wed, Jun 8, 2011 at 2:25 PM, Mikhail P <email address hidden> wrote:
> Paul, what else did you change?
>
> Are you using RAID, or did you see this happening on individually
> mounted devices?
>
> Thanks!
>
> --
> You received this bug notification because you are a direct subscriber
> of a duplicate bug (667656).
> https://bugs.launchpad.net/bugs/666211
>
> Title:
>  maverick on ec2 64bit ext4 deadlock
>
> Status in “linux” package in Ubuntu:
>  Confirmed
>
> Bug description:
>  I created an ami from the official image (ami-505c6924 – region eu-
>  west-1). the rebundled image works fine for a while but ends with
>  nearly 100% iowait and a load of 6000.
>
>  The instance type is m1.xlarge without ebs.
>
>  There are errors in the amazon console before the kernel starts (see attached boot.log):
>  Failed to read /local/domain/0/backend/vbd/161/2049/feature-barrier.
>  Failed to read /local/domain/0/backend/vbd/161/2049/feature-flush-cache.
>
>  If you are lucky you see errors in the syslog like this:
>  INFO: task jbd2/sda1-8:235 blocked for more than 120 seconds.
>  "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>  jbd2/sda1-8 D ffff880003bcd980 0 235 2 0x00000000
>  ffff8801b5f49b20 0000000000000246 0000000000000000 0000000000015980
>  ffff8801b5f49fd8 0000000000015980 ffff8801b5f49fd8 ffff8801b571db80
>  0000000000015980 0000000000015980 ffff8801b5f49fd8 0000000000015980
>
>  The machines are unusable after a few hours. I am testing those images
>  right now. There is no heavy load expected. Karmic images work fine.
>  Packages I've installed are build-essential, git-core, ruby, nginx and
>  couchdb. Node.js is compiled manually.
>
>  The same error is described on Alestic by Jay Freeman, unfortunately he didn't open any bug here:
>  http://alestic.com/2010/10/ec2-ubuntu-maverick#comment-484
>
>  AMI:
>  http://developer.amazonwebservices.com/connect/entry.jspa?externalID=4350
>
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>