INF: Large Incremental Backups

Summary

In some cases, incremental backups in Carbonite Safe Server Backup (CSSB) may be significantly larger than expected and lead to quota issues. When investigating large incremental backups, you should begin by checking for legitimate causes. If a legitimate cause cannot be found, the root cause must be more thoroughly investigated.

Cause:

These causes all share an underlying explanation: files have been modified by a user(s) or because of user actions. Please check for the following known causes:

Modified Files

Large incremental backups can occur due to backing up one or more large files, a larger number of smaller files, or a combination of the two in a single incremental. Incremental backups include any files that are new or modified since the last successful backup. One of the easiest and most reliable ways to check if a large incremental backup is legitimate is determining which files were changed since the last successful backup.

Files are considered modified for any number of reasons, such as:

• Adding new files to a location selected for backup
• Moving files
• Renaming files
• Any action that changes the "modified on" date

You can check for files that meet these criteria using File Explorer. In File Explorer, you can narrow search results to show the file sizes for items modified between certain dates using the size and datemodified search filters.

For example, you can search for files larger than 1 MB using the filter size:, the greater than symbol (>), and "1MB". The operator AND is used to add another search criteria. The datemodified: filter is used to exclude files that were last modified outside the selected date range (or specific date).

Backing Up Backups

It's possible you are using CSSB to protect backups created by other programs. If these backups are large files that are added or modified frequently, this could be adding to the size of your incremental backups.

Scripts

You may be using scripts (either manually or on a schedule) that modify one or more files selected for backup. Any files modified this way will also be included in the next scheduled backup by CSSB.

Solution:

If none of the known causes above explain the large size of incremental backups, check the previous backups in the cycle for any backup failures. Ensure the underlying cause(s) for any such failures are addressed before continuing the backup.

Once the underlying cause has been identified and addressed, start a new full backup to force the start of a new backup cycle.