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Bug 1067477

Summary: ISCSI 30Gig thin provision disk reported as preallocated during writing to it by dd of 25Gig all zeros.
Product: [Retired] oVirt Reporter: Nikolai Sednev <nsednev>
Component: ovirt-engine-coreAssignee: Sergey Gotliv <sgotliv>
Status: CLOSED WORKSFORME QA Contact: bugs <bugs>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 3.4CC: abaron, acanan, acathrow, ebenahar, gklein, iheim, nsednev, sgotliv, yeylon
Target Milestone: ---Keywords: Triaged
Target Release: 3.4.0   
Hardware: x86_64   
OS: Unspecified   
Whiteboard: storage
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2014-02-24 14:31:35 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: Storage RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
VDSM and engine logs none

Description Nikolai Sednev 2014-02-20 14:05:32 UTC
Created attachment 865536 [details]
VDSM and engine logs

Description of problem:
ISCSI 30Gig thin provision disk reported as preallocated during writing to it by dd of 25Gig all zeros.

Version-Release number of selected component (if applicable):
ovirt-engine-3.4.0-0.7.beta2.el6.noarch
qemu-kvm-rhev-0.12.1.2-2.415.el6_5.4.x86_64
libvirt-0.10.2-29.el6_5.3.x86_64
sanlock-2.8-1.el6.x86_64

How reproducible:
Always

Steps to Reproduce:
1.Create ISCSI 30Gig disk as thin provision.
2.After disk is created, attach it to VM with OS already installed on it.
3.Check that disk is shown as thinprovision at engine's WEBUI->Virtual Machines->Disks->Allocation Policy->Thin provision.
4.Start writing to it using dd ie. dd if=/dev/zero of=/dev/vda bs=1M count=25000.
5.When dd finishes, go over topic 3 and see that thin provision changed to preallocated. 


Actual results:
Thin provision changes to preallocated.

Expected results:
Thin provision should stay as is.

Additional info:  engine, vdsm logs.

Comment 1 Sergey Gotliv 2014-02-24 07:00:08 UTC
Nikolai,

Can you, please, reproduce this bug again?

Since you didn't provide disk id/alias or any other disk identifier I had to search logs for 30GB disk and/or vda (2 things that appear in the bug description). 
According to attached logs VM's vda disk is preallocated and the only 30GB disk is preallocated either. 

So I would like to see that disk was created as sparse and then became a preallocated, by the way I tried to reproduce it by myself with smaller sizes and my disk remained sparse after dd.

Comment 2 Elad 2014-03-11 13:22:24 UTC
Sergey, can you please add the reason why this bug was closed?