Bug 574733

Summary:	RHEV nfs soft mounts needs to be changed to hard mounts
Product:	[Retired] oVirt	Reporter:	Dor Laor <dlaor>
Component:	vdsm	Assignee:	Dan Kenigsberg <danken>
Status:	CLOSED DUPLICATE	QA Contact:	yeylon <yeylon>
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	abaron, acathrow, amureini, bazulay, dyasny, iheim, jlayton, mgoldboi, mkenneth, Rhev-m-bugs, sgrinber, srevivo, tburke, ykaul
Target Milestone:	---
Target Release:	3.3.4
Hardware:	All
OS:	Linux
Whiteboard:	storage
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2012-04-05 05:54:32 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	Storage	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Dor Laor 2010-03-18 11:38:35 UTC

Description of problem:
NFS soft mounts can lead to silent data corruptions on write errors. 
It will be wise to change it in rhev-2.2 although late in the game. Even this change might expose other bugs, those shouldn't be drastic as the data corruption one.

Comment 4 Simon Grinberg 2010-03-22 09:25:23 UTC

Using hard mount however, (as I understand the difference between hard and soft mounts), reverts us back to the previous behaviour that the qemu_kvm process hangs on NFS disconnect.

In the past the process was destroyed when this happens for more then 30secs. What is the current behaviour?

We also had another check that run lstat on the NFS mount path - is this one still there? if so we can use the fact that this check does not return to understand that this is NFS freeze and refrain from killing the VM.

There may be other implications that I may not thought of due to this change in behaviour.

Comment 9 Ayal Baron 2012-04-04 14:49:56 UTC

Although there is no known issue with this in our use case it is still recommended to add support for hard mounts as it is much more widely tested at the nfs level.
this requires however supporting intr properly and actually interrupting processes in the control path.

Comment 10 Ayal Baron 2012-04-05 05:54:32 UTC

Closing this bug as duplicate on the upstream bug (this one was opened for rhev and contains irrelevant info).

*** This bug has been marked as a duplicate of bug 810082 ***