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Kernel Error:task jbd2/vda1-8:207 blocked for more than 120 seconds

asked 2015-03-27 01:48:00 -0500

sammit.karekar gravatar image

updated 2015-03-27 02:29:00 -0500

SGPJ gravatar image

Hi there,

I am getting following kernel errors when the VM reboots (Ubuntu).

[2232720.784111] INFO: task jbd2/vda1-8:207 blocked for more than 120 seconds.
[2233415.176909]       Not tainted 3.13.0-29-generic #53-Ubuntu
[2233415.185598] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

Is this something to do with the storage? Please help.

FYI: I am running openstack version 4.

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answered 2015-03-27 09:55:31 -0500

Yes, this is almost certainly storage-related - but what's not clear is whether your VM kept running after seeing this error or not. Are there any errors on the host kernel log? What kind of backing storage are you using - is it just local disks or is something else connected?

If your VM does actually continue running, you could just be filling up the cache faster than it can be cleared. By default Linux uses up to 40% of the available memory for file system caching. After this mark has been reached the file system flushes all outstanding data to disk causing all following IOs going synchronous. For flushing out this data to disk this there is a time limit of 120 seconds by default. In the case here the IO subsystem is not fast enough to flush the data withing 120 seconds. As IO subsystem responds slowly and more requests are served, System Memory gets filled up resulting in the above error, thus serving HTTP requests.

You can check this by changing vm.dirty_ratio and vm.dirty_backgroud_ratio

someuser@servercore [/home/someuser]$ sudo sysctl -w vm.dirty_ratio=10
someuser@servercore [/home/someuser]$ sudo sysctl -w vm.dirty_background_ratio=5
someuser@servercore [/home/someuser]# sudo sysctl -p
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Comments

What to do if the vm stopped running? And do you know the reason why the vm stopped running?

hprasad gravatar imagehprasad ( 2015-07-21 23:43:45 -0500 )edit

i have the same problem(vm stopped running).do you find the answer?

tangyi gravatar imagetangyi ( 2015-10-19 21:08:03 -0500 )edit

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Asked: 2015-03-27 01:48:00 -0500

Seen: 7,243 times

Last updated: Mar 27 '15