[DeltaFileGenerator.emitUnit] There is not enough space on the disk.

OS

Windows

Software

6.17.0.0 - 6.27.0.0

Error message

Not possible to generate Delta file, Microsoft Exchange Server\Microsoft Information Store\DC01\Mailbox Database 0123456789\Mailbox Database 0123456789.edb wil be backupped in its entirety.[com.ahsay.obc.es] [DeltaFileGenerator.emitUnit] There is not enough space on the disk.

Cause

The 6.17 and higher online backup software uses VSS to create a snapshot so that it's not required to copy the entire Exchange database to the temporary folder. The software still has to look for the changes in the database using the in-file-delta technology regardless of generating the incremental or differential delta file and storing it in the temporary folder. This error message means that there wasn't enough free space to store the delta file in the temporary folder. According to the default settings the delta file will not exceed 50% of the original file.

Example:
For a 50GB Exchange database the software will look for a maximum of 50% changed. This means that the maximum size will be 25GB and that the temporary folder needs 25GB of free space.

Solution

Create enough free space on the partition where the temporary folder is located or change the temporary folder to a different location with more space.

1. Open the software
2. Go to the backupset settings (cog)
3. Select the correct backup set
4. Go to the Options tab
5. Change the temporary folder to a partition with more space, optional you could attach a USB drive and select that
6. Save the settings