Return
-
Title
ESXi 6.0 Silent CBT Failure. - Potential Data Loss -
Description
ESXi 6.0 Silent CBT Failure. - Potential Data LossThere is a fault in the ESXi 6.0.x server which could provide incomplete CBT information for incremental backups.The result is that any restored data can not be guaranteed to be correct. There is no way for the NetVault VMware plugin (or any backup product) to check that the faulty data is being sent back.When running virtual machine backups which utilize Changed Block Tracking (CBT) in ESXi 6.0, you experience these symptoms:- The CBT API call QueryDiskChangedAreas() API call can sometimes return incorrect changed sectors, which results in inconsistent incremental virtual machine backups.
- Inconsistent virtual machine backups
-
Cause
VMware coding issue.Therefore this will require a fix from VMware to be applied to the server.It is advisable to warn all customers using vSphere 6.0 that they may be at risk. -
Resolution
Please see the article below from VMware for workarounds or to download the patch to fix this issue.
Please refer to VMware article 2136854 - "Backing up a Changed Block Tracking enabled virtual machine in ESXi 6.0.x returns incorrect changed sectors (2136854)"
VMware Disclaimer:Quest Software does not provide support for problems that arise from improper use of VMware patches.Please make sure to backup your VMware and do a test restore to make sure you have a good backup before applying any patches.