What is Change Block Tracking (CBT)?
Change Block Tracking, or change tracking or CBT is an incremental backup technology for VMware virtual machines (VMs). Like snapshot differentials or delta differencing, CBT backs up only the blocks that have changed, rather than backing up every block of every VM in the infrastructure. It is essentially making a record or a journal of which blocks of a storage object were changed by IO. CBT does not keep track of what data was written, it only logs which areas of object were written. Such data tracking can be used by various applications, primarily backup and restore solutions.
Traditional backup applications rely on snapshot technologies to take backup. Snapshots are essentially point in time copies of the storage object and make the backups consistent. However, it is a tedious task to take backups of the entire object at every backup cycle. To overcome this challenge we use Incremental or differential snapshots.
Calsoft’s CBT Expertise:
- Integration with NFS Ganesha using FSAL for change tracking
- Implementation of CBT driver that can track various block devices and provide bitmaps representing the changed areas over a given time interval.
- CBT Provider development to generate tracking information for any object.
- Tracker Interface development for CBT commands
- CBT Orchestrator development to provide library interfaces for backup agent
Contact Calsoft today to know more about our CBT expertise