Bug 1104602

Summary:	[SNAPSHOT]: op-version is incremented to 4 when a snapshot is created
Product:	[Red Hat Storage] Red Hat Gluster Storage	Reporter:	Rahul Hinduja <rhinduja>
Component:	snapshot	Assignee:	Avra Sengupta <asengupt>
Status:	CLOSED ERRATA	QA Contact:	Rahul Hinduja <rhinduja>
Severity:	high	Docs Contact:
Priority:	urgent
Version:	rhgs-3.0	CC:	asengupt, kparthas, nsathyan, rhs-bugs, ssamanta, storage-qa-internal
Target Milestone:	---
Target Release:	RHGS 3.0.0
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	SNAPSHOT
Fixed In Version:	glusterfs-3.6.0.16-1.el6rhs	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:
Clones:	1104944 (view as bug list)		Environment:
Last Closed:	2014-09-22 19:40:34 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:
Bug Depends On:
Bug Blocks:	1104944

Description Rahul Hinduja 2014-06-04 10:21:07 UTC

Description of problem:
=======================

When a volume snapshot is created, the op-versio of snapshoted volume is set to 4. For example, if the op-version of the volume is 3 and a snapshot is taken of a volume, than the op-version of snap volume is set to 4. Ideally it should be what is set for a volume.

op-version of a volume before snapshot is created is 2:
=======================================================

[root@inception ~]# cat /var/lib/glusterd/vols/vol2/info | grep op-version
op-version=3
client-op-version=2
[root@inception ~]#

Created a snapshot of a volume and checked its op-version it is 4:
==================================================================

[root@inception ~]# gluster snapshot create snapshot1 vol2
snapshot create: success: Snap snapshot1 created successfully
[root@inception ~]# cat /var/lib/glusterd/snaps/snapshot1/25861da271434f86a896e6101ca31345/info | grep op-version
op-version=4
client-op-version=2
[root@inception ~]# 

Restore a volume to snapshot1 and check the op-version of the volume it is 4:
=============================================================================

[root@inception ~]# gluster volume stop vol2
Stopping volume will make its data inaccessible. Do you want to continue? (y/n) y
volume stop: vol2: success
[root@inception ~]# gluster snapshot restore snapshot1
Snapshot restore: snapshot1: Snap restored successfully
[root@inception ~]# cat /var/lib/glusterd/vols/vol2/info | grep op-version
op-version=4
client-op-version=2
[root@inception ~]# 


The impact of this is unknown to me but what is discussed is that the client might not be able to reconnect. Raising the bug with high priority.

Version-Release number of selected component (if applicable):
=============================================================

glusterfs-3.6.0.12-1.el6rhs.x86_64


How reproducible:
=================
1/1


Steps to Reproduce:
===================
1. Create and start a volume
2. Check the volume op-version
3. Create a snapshot of a volume
4. Check the snapshot volume op-version

Actual results:
===============
op-version of snap volume is set to 4 whereas the op-version of a volume is different (could be 2/3)


Expected results:
=================

The op-version of snap volume should not be bumped up, it should remain as of original volume

Comment 3 Avra Sengupta 2014-06-05 06:48:36 UTC

Upstream patch in review at http://review.gluster.org/#/c/7986/

Comment 4 Avra Sengupta 2014-06-11 08:47:33 UTC

Fix at https://code.engineering.redhat.com/gerrit/26663

Comment 5 Rahul Hinduja 2014-06-12 09:39:00 UTC

Verified with build: glusterfs-3.6.0.16-1.el6rhs.x86_64

As per bz 1096425 comment 8, (the op-versions will be multi-digit integer values composed of the version numbers, instead of a simple incrementing integer. An X.Y.Z release will have XYZ as its op-version.)

Initial op-version: 30000
=========================

[root@inception ~]# cat /var/lib/glusterd/vols/vol0/info | grep op-version
op-version=30000

op-version of snapshot: 30000
==============================

[root@inception ~]# cat /var/lib/glusterd/snaps/snap1/a8097ef84c334a69a3a0ca2e1ebf9649/info 
type=2
count=4
status=1
sub_count=2
stripe_count=1
replica_count=2
version=2
transport-type=0
volume-id=a8097ef8-4c33-4a69-a3a0-ca2e1ebf9649
username=135b4afb-bdb7-4144-bffa-679cd1ad6df9
password=30d86d36-adbb-4f44-b393-5049d93f0622
op-version=30000

After Restore: 30000
====================

[root@inception ~]# cat /var/lib/glusterd/vols/vol0/info | grep op-version
op-version=30000


Moving the bug to verified state

Comment 7 errata-xmlrpc 2014-09-22 19:40:34 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHEA-2014-1278.html