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Best Practices for Veeam Backup & Replication 7.0 for VMware

Veeam Management Pack Help Center  > Best Practices for Deployment & Configuration >  Understanding Veeam Backup & Replication Options > How It Works: Backup Methods > Forward Incremental

Forward Incremental

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When using the incremental backup method, a full backup file (.VBK) is created during the first backup run, exactly like reverse incremental mode. However, subsequent backups save only the changed blocks since the last performed backup (whether full or incremental) into an incremental backup file (.VIB) next to the full backup.

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When using incremental backups, it is required that a full backup be scheduled occasionally to start a new chain. Veeam offers two ways to create a new full backup.

The first option is a feature called Synthetic Full. This feature takes the old full backup and the incremental backups in the chain to combine them into a new full backup. This method requires no additional I/O on the source VM, however, it creates significant I/O on the target. This I/O can sometimes cause an issue when using slower backup targets.

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As part of creating a synthetic full, Veeam offers the option to transform the incremental segments into reverse incremental backups, providing a hybrid approach that allows many of the benefits of both the reverse and forward incremental methods, at the cost of additional I/O on the target.

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A synthetic full can be created on specific days of the week, and as often as every day, or as little as once a week.

The other option for starting a new backup chain is simply to schedule the job to perform an Active Full backup at specific intervals. This will, of course, have some impact on the source storage as it is a standard full backup, which will require retrieving all data from the source storage, but this can be scheduled for once a week (or once a month, or various other schedules) to meet the environments retention policy requirements.

Below are some pros and cons of full backup method:

Advantages

Considerations

Backup files are not changed after they are written - this is important when writing to a dedupe appliance.

Requires one of the following:

Synthetic Full — takes significant amount of time and I/O on target storage (2x read, 2x write during synthetic full operation)

Active Full — a periodic full backup which impacts production. Note that it uses more raw space (not typically an issue when used with dedupe storage)

Easier for GFS (‘grandfather-father-son’) style staged retention policies - just copy weekly VBKs and delete unneeded incremental backups.

Works well with dedupe storage - required full backups are highly deduped with previous fulls.

Backups can continue even when earlier backup files are being used by virtual labs - this is important if utilizing SureBackup.

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