Which Backup Strategy To Choose - ACRONIS RECOVERY - FOR MS SQL SERVER Manual

A full backup contains all data at the moment of backup creation – a complete
database or instance. You can recover the entire database by restoring the database
from a full database backup to a chosen location. Enough of the transaction log is
included in the backup to let you recover the database to the time when the backup
finished. When the database is recovered, uncommitted transactions are rolled back.
The restored database matches the state of the original database when the backup
finished, minus any uncommitted transactions.
For a small database that can be backed up quickly, it is convenient to use only full
database backups. However, as the database becomes larger, full backups take more
time to finish and require more storage space. Therefore, for a large database, you
might want to supplement full database backups with differential backups.
A full backup can form a base for further differential backup or can be used as a
standalone archive.
A differential backup creates an independent file, containing all changes made
against the initial full archive.
A standalone full backup may be an optimal solution if you often roll back the database
to the initial state. In this case, you do not need to re-create the initial full backup, so
the backup time is not crucial, and the restore time will be minimal.
Alternatively, if you are interested in saving the last data state to be able to restore it
in case of a database failure, consider the differential backup. It is particularly effective
if your data changes tend to be small in comparison to the full data volume.
The transaction log records all transactions and database modifications made by
each transaction. The transaction log is a crucial component of the database and, if
there is a system failure, the transaction log might be required to bring your database
back to a consistent state.
If you are backing up filegroups, the transaction logs will be backed up along with the
full backup. Backing up transaction logs prevents data loss after the last backup and
lets you restore the database state to an arbitrary point in time in order to undo the
harmful changes.
To choose the appropriate backup method (or methods), you have to identify the
requirements for the availability of your data in order to choose the appropriate backup
strategy. Your overall backup strategy defines the type and frequency of backups as
well as the type and capacity of the hardware required for the archive location. See
5.1.3 "Which Backup Strategy to Choose?" for our recommendations.

5.1.3 Which Backup Strategy to Choose?

Follow the recommendations below to define the best backup strategy for your
organization:
•
Database activity is low to medium:
- Full backup once a week
- Differential backup once a day
- Transaction Logs backup every two to four hours
• Database size is small to medium, but activity is high:
- Full backup twice a week
- Differential backup twice a day
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