5 1 0:Backup Level

Overview

SEP sesam provides four different backup levels: full, differential, incremental and copy. The backup level is specified when creating a backup event or performing an immediate start of the backup.

When planning your backup strategy, it is essential to consider the advantages and disadvantages of different backup levels, particularly in terms of time and storage space. A common approach is to use a combination of FULL, DIFF, and/or INCR backups as part of a structured backup chain.

SEP sesam retention management ensures that all backups in a chain are kept as long as the most recent backup remains valid. Long chains with many backups can become inefficient and vulnerable, potentially leading to restore failures due to storage limitations or prolonged restore times. Since there is no built-in limit for backup chain length, SEP AG recommends scheduling regular FULL backups and limiting the number of consecutive incremental backups to a maximum of 100.

The following backup levels are available:

FULL backup

Full backup captures all data specified by the backup task, regardless of whether changes have occurred. It creates a complete snapshot of the data at the current point-in-time. A full backup might take longer to perform, but offers straightforward restore where only one saveset is required to restore the entire dataset. Full backups serve as the starting point for subsequent differential (DIFF) and/or incremental (INCR) backups, forming a backup chain.

Information about the backup status is stored in the SEP sesam database. Note that on Windows the archive bits are not automatically deleted. To purge the archive bits, the command -o clear_archive can be used in the backup options.

DIFF (differential) backup

Differential backup captures data that has changed or been created since the last full backup. Each differential backup creates a point-in-time backup of all changes since the last full backup, disregarding all other intermediate differential and incremental backups. A differential backup is faster to perform than a full backup, but two savesets are required for restore – the saveset from the last full backup and the saveset from the most recent differential backup.

INCR (incremental) backup

Incremental backup captures the changes made since the last backup, whether it was a full, differential, or incremental backup. Incremental backups are space-efficient, fast, and provide the most frequent data captures in a backup chain. For restore, the last full saveset, the last differential saveset (if it exists) and all subsequent incremental backup savesets are required, which may extend the restoration time. The restore process sequentially applies these savesets to restore data to a specific point-in-time. SEP sesam offers generation restore, which offers high level of granularity and flexibility for data recovery. Each incremental backup creates a new generation of the data. The exact point in time can be selected for restore and SEP sesam applies the incremental backups sequentially from the last full backup, replaying the changes made over time.

COPY backup

Copy backup is a full backup that operates independently of other backups. It creates a standalone backup of the data at that moment. It is useful for archival purposes or for creating a backup copy for specific use cases. Copy backups are not part of a backup chain and don't impact other differential or incremental backups in a backup chain.

	Note
	Differential (DIFF) and incremental (INCR) backups rely on a full backup as a reference point. If no initial FULL backup exists, the first DIFF or INCR backup is automatically performed as a FULL backup to maintain the backup chain and ensure data consistency.

See also

Standard Backup Procedure – About Backup – Creating a Backup Event

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