By default, Veeam Backup & Replication does not copy "dirty" data blocks to the target location. Dirty data blocks are blocks marked as deleted after you remove them from the recycle bin. Omitting these blocks lets you reduce the size of the VM backup or replica and increase the job performance.
If you do not want to exclude deleted file blocks from backups or replicas, you can disable the Exclude deleted file blocks option in the backup or replication job settings.
If you enable or disable the Exclude deleted file blocks setting for the existing job, Veeam Backup & Replication will apply the new setting from the next job session.
With this option enabled, Veeam Backup & Replication performs the following operations during the job session:
- Veeam Backup & Replication accesses the MFT file on the VM guest OS to identify deleted file blocks, and zeros out these blocks.
- Veeam Backup & Replication processes and transports data blocks of the VM image in the following manner:
- If a data block of the VM image contains only the deleted file blocks, Veeam Backup & Replication does not read this data block from the source volume.
- If a data block of the VM image contains zeroed out blocks and other data, Veeam Backup & Replication copies this block to the target. Due to data compression, data blocks that are marked as deleted are compressed, and the size of the resulting backup or replica file reduces.
Limitations for Deleted File Blocks Exclusion
Veeam Backup & Replication can exclude deleted file blocks only on the VM guest OS with Microsoft NTFS.