Bug 1392172

Summary: dump uses all available memory and then system reboots
Product: [Fedora] Fedora Reporter: dan
Component: dumpAssignee: Josef Ridky <jridky>
Status: CLOSED EOL QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 24CC: dan, jridky, phracek
Target Milestone: ---   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2017-08-08 19:08:48 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Attachments:
Description Flags
systemd journal none

Description dan 2016-11-05 15:16:02 UTC
Created attachment 1217567 [details]
systemd journal

Description of problem:

For a number of years I have used dump/restore to make filesystem backups.  My current methodology is to boot to rescue.target, enable networking using the iup script, and then to mount a remote nfs share where the backups are to be stored.

I recently noticed that some needed restores were failing and determined that my backups were not cleanly finishing.  Further analysis showed that after some time almost all of the 16GB of system memory was being used for cache buffers.

This is reproducible 100% of the time.  At some point, no memory would be available for other processes and the system would reboot.

To work around this issue I now boot into rescue.target and assign the bash shell to a cgroup which limits memory to 1GB.  This has stabilized the situation and proved effective.

This did work properly up until around FC23.  If this is not a dump problem per-se but some other system issue around rescue mode please feel free to reassign.

I've attached a capture from the system journal, but it is a bit confusing towards the end because when the system rebooted time was not immediately synchronized, so some post boot records are mixed in with pre-crash.  But you'll see the system frantically trying to do some memory management before giving up.

Comment 1 dan 2017-01-02 14:34:35 UTC
While I don't see that there has been any specific activity of this report, I tested again under FC25, kernel 4.8.14-300, and dump-0.4.0-30.b46.  While almost all system memory is still used by buffers the system remains stable and does not crash.  I'll leave this open for a while in case anyone else encounters it and wishes to update.

Comment 2 Fedora End Of Life 2017-07-25 23:46:34 UTC
This message is a reminder that Fedora 24 is nearing its end of life.
Approximately 2 (two) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 24. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as EOL if it remains open with a Fedora  'version'
of '24'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version'
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not
able to fix it before Fedora 24 is end of life. If you would still like
to see this bug fixed and are able to reproduce it against a later version
of Fedora, you are encouraged  change the 'version' to a later Fedora
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's
lifetime, sometimes those efforts are overtaken by events. Often a
more recent Fedora release includes newer upstream software that fixes
bugs or makes them obsolete.

Comment 3 Fedora End Of Life 2017-08-08 19:08:48 UTC
Fedora 24 changed to end-of-life (EOL) status on 2017-08-08. Fedora 24 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this
bug.

Thank you for reporting this bug and we are sorry it could not be fixed.