VM /ETC

Posts Tagged ‘change block tracking’

Tom Howarth, VMware Communities Moderator and blogger at PlanetVM.net, posted this week how he was informed by a developer of a virtualization backup vendor about a scenario involving reverting to an ESX snapshot that results in corrupted incremental backups when using vSphere’s Change Block Tracking (CBT). Howarth’s post Major issue with Change Block Tracking recounts his conversation and exploration of the problem with the developer. In summary, Howarth reported “there is a major issue with the way VMware handles the indexing of the ChangeID.”

Almost a week later and after a flurry of comments from most of the vendors leveraging CBT for virtual machine backups, VMware has published a KB article on the subject.

VMware KB: Reverting to a pre-existing snapshot under specific conditions can cause incremental backups based on CBT (Changed Block Tracking) to become inconsistent

The KB Article describes the exact scenario that causes the problem:

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