[CentOS-virt] vm.dirty_ratio

Wed Dec 7 14:42:04 UTC 2016
-=X.L.O.R.D=- <xlord.sl at gmail.com>

Dear,
It is either one of the task hold and time out due to system memory resource
management of Linux

Explain
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.

Source -->
https://www.blackmoreops.com/2014/09/22/linux-kernel-panic-issue-fix-hung_ta
sk_timeout_secs-blocked-120-seconds-problem/

Hope that helps!
Xlord

-----Original Message-----
From: CentOS-virt [mailto:centos-virt-bounces at centos.org] On Behalf Of Gokan
Atmaca
Sent: Wednesday, December 7, 2016 10:16 PM
To: Discussion about the virtualization on CentOS <centos-virt at centos.org>
Subject: Re: [CentOS-virt] vm.dirty_ratio

> Please check if there is also error log contained OOM kill?
It does not appear.

On Wed, Dec 7, 2016 at 4:41 PM, -=X.L.O.R.D=- <xlord.sl at gmail.com> wrote:
> Dear,
> Please check if there is also error log contained OOM kill?
>
> Xlord
>
> -----Original Message-----
> From: CentOS-virt [mailto:centos-virt-bounces at centos.org] On Behalf Of 
> Gokan Atmaca
> Sent: Wednesday, December 7, 2016 9:16 PM
> To: Discussion about the virtualization on CentOS 
> <centos-virt at centos.org>
> Subject: [CentOS-virt] vm.dirty_ratio
>
> Hello
>
> I get the following error on the server. The problem is resolved when 
> you restart. But is this causing the problem?
>
> messages_log:
> INFO: task jbd2/dm-1-8:674 blocked for more than 120 seconds echo 0 > 
> /proc/sys/kernel/hung_task_timeout_secs
>
> Thanks.
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> CentOS-virt mailing list
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