Backing up open files and databases

Overview

Backing up files that are constantly being written to may require more consideration than backing up files that are changed less frequently, such as documents, pictures, or other media files. This article describes best practices for backing up open files and databases.

Considerations

• The CrashPlan app backs up open files by default.
• The method used to back up open files varies by operating system.

Best practices for open files

The CrashPlan app backs up open files by default so that users don't have to stop working in order to protect their files. Open file backup behavior varies on each operating system:

• Mac - A non-exclusive read is acquired on the file while backing up.
• Linux - A non-exclusive read is acquired on the file while backing up.
• Windows - A Volume Shadow Copy Service (VSS) snapshot is created and then the snapshot is read for backup. It is possible that all the files needed for a usable backup are not backed up at the same time.

We recommend leaving the Back up open files setting enabled to ensure open files are included in backups. If files often fail to back up because they're open or in use, adjust your backup schedule so CrashPlan runs during off-hours when the computer isn't being used and files are closed.

Best practices for databases

To ensure the data integrity of backups, we recommend backing up static database dumps rather than live database files.

Databases are dynamic, constantly writing to various files and logs simultaneously. If a database modifies a record after the data file is backed up but before the transaction log is backed up, the resulting database in the backup will be internally inconsistent. If restored, these inconsistencies can lead to data corruption.

Creating a database dump avoids this problem by saving a point-in-time snapshot of the database contents. This guarantees the integrity of the data when the CrashPlan app backs up the resulting dump file.