Error Number 0x70: There is not enough space on the disk

OS

Windows

Software

Microsoft Exchange

Error Message

CExBackup::backupFile:WriteFile Path=H:\TEMP\...: Error Number 0x70: There is not enough space on the disk.

Cause

Means that there is no free space left on the Exchange-server itself.
The Exchange database backup works as follows:

1. Mindtime Backup requests the Exchange-server (trough a API call) to create a copy of the Exchange-database.
2. The Exchange-server 'freezes' the database but keeps functioning by storing all requests in log files.
3. The database is copied by Exchange to the temporarily directory.
4. After the copy is completed the Exchange server releases the database, processes the log files and continues normal operations.
5. Mindtime Backup reads the database copy and creates an incremental/differential file.

This process means that the temporarily directory can become 1.5 times the size of the Exchange database during a backup operation.
(1x the size of the database and according to the default In-File delta settings the software is allowed to backup a maximum of 50% changes which is the .5) That's why the temporarily directory has the be on a disk with a minimum of 1.5 times the size of the Exchange server in free space.
It's recommended to select a non critical disk so the system wont crash due to insufficient disk space.

Solution

If there is no active backup the contents of the temporarily directory can be erased to create free space.
In some cases the software won't cleanup the temporarily directory and this has to be done manually or you can use a pre-command to remove the temporarily files prior to the backup starting.
Remove the content of the temporarily directory and choose a directory in the backupset settings on a disk with at least 1.5 times the size of the Exchange server.