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Bug 1090079

Summary: vdsm reports guest as paused on any IO error, even if libvirt/qemu policy is set to "report"
Product: Red Hat Enterprise Virtualization Manager Reporter: rhev-integ
Component: vdsmAssignee: Francesco Romani <fromani>
Status: CLOSED ERRATA QA Contact: Pavel Novotny <pnovotny>
Severity: high Docs Contact:
Priority: medium    
Version: 3.2.0CC: adahms, bazulay, dgibson, gklein, iheim, lpeer, mavital, michal.skrivanek, mkalinin, sherold, yeylon
Target Milestone: ---Keywords: Patch, Reopened, ZStream
Target Release: 3.3.3   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: virt
Fixed In Version: vdsm-4.13.2-0.14.el6ev Doc Type: Bug Fix
Doc Text:
Previously, VDSM would report that virtual machines experiencing any I/O error were in a paused state. This was caused by the logic used by VDSM to check I/O errors received from libvirt. Now, the logic used to check such errors has been revised so that VDSM detects the nature of the error, allowing I/O errors to be correctly reported and handled.
 Story Points: ---
Clone Of: 1064630 Environment:
Last Closed: 2014-05-27 08:57:34 UTC Type: ---
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: 1064630    
Bug Blocks:    

Comment 3 Pavel Novotny 2014-05-05 14:54:40 UTC 
Verified in vdsm-4.13.2-0.14.el6ev.x86_64 (is36).

Verification steps:

I used local storages on the host.
One "regular" under `/mnt/localstorage/`.
And a second "flakey" one under `/mnt/errstorage/`, simulating I/O errors using `dmseup` utility:
-~-
# dd if=/dev/zero of=/tmp/virtualblock.img bs=4096 count=1M
1048576+0 records in
1048576+0 records out
4294967296 bytes (4,3 GB) copied, 50,7873 s, 84,6 MB/s
# losetup /dev/loop7 /tmp/virtualblock.img 
# mkfs.ext4 /dev/loop7 
mke2fs 1.41.12 (17-May-2010)
Discarding device blocks: done                            
...
...
### following command creates a flakey device with random I/O errors
# dmsetup create errdev0
0 8388608 flakey /dev/loop7 0 9 1
# mkdir /mnt/errstorage
# chown -R vdsm:kvm /mnt/errstorage
# mount /dev/mapper/errdev0 /mnt/errstorage/
-~-

In RHEVM GUI, add both local storages (/mnt/localstorage as master SD).
Create new VM with two disks - one "healthy" disk on the `localstorage` domain and a second "flakey" disk (1G) on the `errorstorage` domain.

In RHEVM DB, update both disks to propagate errors to guest: psql: UPDATE base_disks SET propagate_errors = 'On';
Restart ovirt-engine service.

In RHEVM GUI, install the guest OS *on the healthy disk* (I used Fedora 19).
In the guest, mount the second flakey disk to `/mnt/errdisk/` and run some I/O operation on it.
I used `dd`: # dd if=/dev/zero of=/mnt/errdisk/test bs=1000 mount=1M
and after few seconds I got a splash of I/O errors "Buffer I/O error on device vdb, logical block ...".

Results:
The qemu process runs with correct parameter 'werror=enospc'.
After the I/O errors, the guest is still running.
Both, QEMU/VDSM and RHEVM, are also reporting the guest as running.
Comment 5 errata-xmlrpc 2014-05-27 08:57:34 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/RHBA-2014-0548.html