A backup system uses client/server architecture with a backup server and multiple backup clients. The backup server manages the backup operations and maintains the backup catalog, which contains information about the backup process and backup metadata. The backup server depends on backup clients to gather the data to be backed up. The backup clients can be local to the server or they can reside on another server, presumably to back up the data visible to that server. The backup server receives backup metadata from the backup clients to perform its activities.

The storage node is responsible for writing data to the backup device (in a backup environment, a storage node is a host that controls backup devices). Typically, the storage node is integrated with the backup server and both are hosted on the same physical platform. A backup device is attached directly to the storage node’s host platform. Some backup.

Architecture refers to the storage node as the media server because it connects to the storage device. Storage nodes play an important role in backup planning because they can be used to consolidate backup servers.

The backup process is based on the policies defined on the backup server, such as the time of day or completion of an event. The backup server then initiates the process by sending a request to a backup client (backups can also be initiated by a client). This request instructs the backup client to send its metadata to the backup server, and the data to be backed up to the appropriate storage node. On receiving this request, the backup client sends the metadata to the backup server. The backup server writes this metadata on its metadata catalog.

Figure: Backup Architecture and process

The backup client also sends the data to the storage node, and the storage node writes the data to the storage device.

After all the data is backed up, the storage node closes the connection to the backup device. The backup server writes backup completion status to the metadata catalog.

Backup software also provides extensive reporting capabilities based on the backup catalog and the log files. These reports can include information such as the amount of data backed up, the number of completed backups, the number of incomplete backups, and the types of errors that may have occurred. Reports can be customized depending on the specific backup software used.

RESTORE process/operations:

• After the data is backed up, it can be restored when required. A restore process must be manually initiated. Some backup software has a separate application for restore operations. These restore applications are accessible only to the administrators. Figure depicts a restore process.

    Figure:  Restore operation

• Upon receiving a restore request, an administrator opens the restore application to view the list of clients that have been backed up. While selecting the client for which a restore request has been made, the administrator also needs toidentify the client that will receive the restored data. Data can be restored on the same client for whom the restore request has been made or on any other client.

• The administrator then selects the data to be restored and the specified point in time to which the data has to be restored based on the RPO. Note that because all of this information comes from the backup catalog, the restore application must also communicate to the backup server. The administrator first selects the data to be restored and initiates the restore process. The backup server, using the appropriate storage node, then identifies the backup media that needs to be mounted on the backup devices. Data is then read and sent to the client that has been identified to receive the restored data.