Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.

Bug 1152265

Summary:	Documentation Update to Warn about localhost NFS mounts
Product:	[Community] GlusterFS	Reporter:	Charles Williams <chuck>
Component:	doc	Assignee:	bugs <bugs>
Status:	CLOSED EOL	QA Contact:
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	3.5.2	CC:	bugs
Target Milestone:	---	Keywords:	Documentation, Triaged
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-06-17 15:57:04 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:
Embargoed:

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.