Bug 1152265 - Documentation Update to Warn about localhost NFS mounts
Summary: Documentation Update to Warn about localhost NFS mounts
Keywords:
Status: CLOSED EOL
Alias: None
Product: GlusterFS
Classification: Community
Component: doc
Version: 3.5.2
Hardware: All
OS: Linux
unspecified
high
Target Milestone: ---
Assignee: bugs@gluster.org
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2014-10-13 18:10 UTC by Charles Williams
Modified: 2016-06-17 15:57 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2016-06-17 15:57:04 UTC
Regression: ---
Mount Type: ---
Documentation: ---
CRM:
Verified Versions:
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Description Charles Williams 2014-10-13 18:10:53 UTC
Description of problem: As many know, and more importantly many do not know, localhost (loopback) NFS mounts can lead to deadlocks under heavy load. There should be a warning in the documentation regarding this bug. Although it is NOT a GFS bug it can and will cause problems for those without the knowledge that I learned the hard way today on a production server.


Version-Release number of selected component (if applicable): I would imagine this applies to all versions until the kernel is patched.


How reproducible: mount a localhost with nfs and rsync ca. 10+ GB files (not sure what the lower limit is and I tried ca 11 GB when it deadlocked)


Steps to Reproduce:
1. mount local volume per nfs
2. copy files
3. wait for deadlock and recover the server while hoping for no major damage

Actual results: deadlock


Expected results: no deadlock


Additional info: I was thinking the warning could be added here: https://github.com/gluster/glusterfs/blob/master/doc/admin-guide/en-US/markdown/admin_settingup_clients.md#nfs

Comment 1 Niels de Vos 2014-10-21 18:07:01 UTC
http://lwn.net/Articles/595652/ contains a fairly complete description. Note that the changes mentioned in the article can be made for the Linux kernel NFS-server, but not for an NFS-server in user-space.

Comment 2 Niels de Vos 2016-06-17 15:57:04 UTC
This bug is getting closed because the 3.5 is marked End-Of-Life. There will be no further updates to this version. Please open a new bug against a version that still receives bugfixes if you are still facing this issue in a more current release.


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