Dear all,

As indicated on http://www.linux-kvm.org/page/Bugs, I am seeking directions as to where to post the following bug (or support request):

"I am running KVM virtualization hosts both with Centos 6 and Centos 7 (all installed from packages and updated to the current version). The guests are Centos, Debian, Windows 2008 R2 and Windows 7 machines. I am using qcow2 virtual disks with virtio drivers and cache disabled throughout. My aim is to take a backups based live snapshots each night.

Since some months ago, I am facing the problem, that backups fail unpredictably. A failed backup does not generate a backup file and thereafter, snapshots can no longer be created or deleted and the guest cannot be started anymore. The resulting error message is "File too large".

The consequence is lack of stability as the guests can no longer be rebooted. If the backup did work needs to be - at least with my means and skills - checked manually. If the problem occurred, the guests needs to be recreated from the last backup with all database and version issues.

This happens both with linux and windows guests. It happens with guests in use for many months and recently created guests. It happens with large and small files (my range ca. is 5GB to 60GB per guest). It happens on Centos 6 and 7 based kvm hypervisors and regardless if the storage consists of a local Raid 1 array or an nfs share on a NAS drive.

There are no apparent disk, ram, swap or configuration issues. Logfiles are not revealing useful information as far as I can tell. Searching forums, I finds similar questions sometimes, but usually in the context of Windows vhd only. More similar forum requests did remain unanswered.

Please point me to a direction I could look to for a solution."

Regards,

Michael Schefczyk
___________________________________________________________ 
Technische Universität Dresden
Fakultät Wirtschaftswissenschaften
Lehrstuhl für Entrepreneurship und Innovation
Prof. Dr. Michael Schefczyk
D-01062 Dresden 
 
Fon: +49-3 51-4 63-3 68 81 
Fax: +49-3 51-4 63-3 68 83 
www.gruenderlehrstuhl.de