There is an updated version of the server side components which offers a new keyword, MAXTRANSFERSIZE
Download from: ftp://ftp.red-gate.com/SQB18.104.22.1681.zip
Copy SQBServerSetup.exe and SQLBackupC.exe to the installation directory. To upgrade the server components run SQBServerSetup.exe. Alternatively you can upgrade each instance from the GUI by selecting the SQL Server instance in the left hand panel, right click and select Install/upgrade server components
MAXTRANSFERSIZE indicates to SQL Server the maximum size of each block of memory that it uses to store backup data, prior to SQL Backup compressing/encrypting the data.
MAXTRANSFERSIZE = 1048576 (1 MB) (default)
MAXTRANSFERSIZE = 524288 (512 KB)
MAXTRANSFERSIZE = 262144 (256 KB)
MAXTRANSFERSIZE = 131072 (128 KB)
MAXTRANSFERSIZE = 65536 (64 KB)
master..sqlbackup N'-SQL "BACKUP DATABASE [DatabaseA] TO DISK = ''<AUTO>'' WITH COMPRESSION = 1, MAXTRANSFERSIZE = 524288"'
master..sqlbackup N'-SQL "RESTORE DATABASE [DatabaseA] FROM DISK = ''C:\\DatabaseA.sqb''WITH RECOVERY, MAXTRANSFERSIZE = 262144"'
This is particularly useful if you experience an error such as "Failed to close vdi".
In this case the VDI.log will show for example
"Error at ServerBufferAreaManager::Allocate: Map buffers Status Code: 8, x8
Explanation: Not enough storage is available to process this command."
In this case you can use the MAXTRANSFERSIZE keyword with a lower value than the 1MB default, e.g. MAXTRANSFERSIZE = 524288