In our ongoing (sort-of pilot) migration from VMware vSphere 5.5 to Microsoft Hyper-V 2012 R2, we encountered a very concerning and puzzling issue with backups. The transition had been smooth for the most part and we used the project to bring aging Windows/SQL 2008 servers up to 2012 R2 and 2014, respectively. Two of our SQL environments had moved over just fine and were being backed up successfully with Microsoft Data Protection Manager 2012 R2 for the time being (other products are being considered, including Veeam). The third of such SQL environments ran into a host of VSS errors once its data was populated and a backup attempted.
- Hypervisor: vSphere 5.5 to Hyper-V 2012 R2
- Guest OS: Windows Server 2008 to 2014
- Backup product: EMC Avamar 7.0.1 to MS DPM 2012 R2
- Backup method: Crash-consistent image to VSS-quiesced image
We had seen an occasional VSS-related backup failure from time to time in DPM, but most were tied to available disk space for the protection group (DPM doesn’t do so well with deduplication of images, so growing has been near-continual). Retrying didn’t make a difference this time, though. We restarted VSS writers and even took downtime to restart the VM. Still the same failure.