The following block diagram illustrates the SAP DB components that are involved when you back up and restore data, and shows how they work together with an external backup tool.
By using the Database Manager client, you enter the command for saving data and in doing so you call the program DBM server. If you are using a UNIX operating system, the DBM server creates one or more pipes. If you use Microsoft Windows, the pipes are created by the database kernel. The DBM server transfers the information to the database kernel to start the backup process. As soon as the data is written to the pipes, the program DBM server calls the external backup tool. The backup tool reads the data from the pipes and saves it on a permanent medium.
By using the Database Manager client, you enter the command for restoring data and in doing so you call the program DBM server. If you are using a UNIX operating system, the DBM server creates one or more pipes. If you use Microsoft Windows, the pipes are created by the database kernel. The program DBM server transfers the information to the database kernel to start the restore process. The program then calls the external backup tool and transfers the information about which backup has to be restored. The client of the backup tool requests the specified backup medium from the backup server. The server gets the medium, reads the data of the backup, and transfers the data to the client of the backup tool. The client writes the data into the pipes. There the data is read by the database kernel and transferred to the database system.