Functional Principle

Basics

The software is used for automated archiving of data files on hard disks. Except for the initial setup and configuration, the programs do not require any user interaction. Log files and e-mail messages are used for communication with the user.

The process is controlled via configuration data in the XML format. There is no user interface.

The software is optimized for archiving of user data from a file server. The files are being copied using the mechanisms of the operating system including the access rights, if desired. A file will not be copied if access to the file is denied. This may e.g. happen in the case of database or system files.

FullBackup and IncrementalBackup

CPTec Backup comprises two programs for archiving of data:

• FullBackup is used for archiving of complete drives/paths/shared folders, e.g. for a complete backup created every week. It copies all files. It copies empty folders. It deletes the target folder (incl. DateFolder) if it is present already, e.g. if the backup is started several times on the same day.

• IncrementalBackup only archives data that have changed since the last backup, e.g. for a daily backup created in the evening. It creates folders which are required for the directory structure. It copies files into an already present target folder by overwriting. IncrementalBackup may also be started several times a day. In this case all changes that occur during the day will add up.

Application

Full backup (FullBackup.exe)

• All files and folders are being copied
• The archive bits for the source files are reset in general

Differential backup (IncrementalBackup.exe without reset of archive bit)

• Copies only files and folders whose archive bit is set
• The archive bits for the source files are not reset
• Regular creation of full backups is required additionally

Incremental backup (IncrementalBackup.exe with reset of archive bit)

• Copies only files and folders whose archive bit is set
• The archive bits for the source files are reset
• Regular creation of full backups is required additionally
• Requires less space than a differential backups, but the effort for restoring the data is higher

Terminology

The configuration file contains definitions for sources and for targets.

Source: A source for the backup. The drive/folder/shared folder that is to be copied. Every source is marked by a short and distinct name. As an example, a folder containing the personal data of all users may be called "PRIVATE" oder "USER".

Target: A target for the backup. The drive/folder/shared folder into which the data are to be copied.

SwitchTarget: A special target that will be selected from a list of defined targets. Depending on the contents of the listed "possible" targets, the one will be selected automatically that has not been a backup target for the longest period of time. The date of the last backup in such a target will be determined by checking the comprised DateFolders and not by checking the date and time stamps in the file system.

DateFolder: The date folder. A folder that will be created automatically on the target in order to arrange the individual backups according to the backup date. Using the format "YYMMDD", these folders will be named according to the backup date, e.g. "050907" for September 07, 2005. The date at the start of the backup is relevant for this. The <DayOffset Hours="n" /> command may be used to correct this date with respect to the real system time. The name of this folder will later on be used by the software to determine which DateFolder is to be deleted if the disk space on the target is getting short. When sorting in alphabetical order, this nomenclature makes sure that the backups on the target are also displayed in chronological order.

SourceFolder: The source folder. A folder that will be created on the target inside of the DateFolder for each copied source. The name of the related source is used as the name for this folder.

Backup sequence

Starting the backup

After CPTec Backup has been installed and the configuration for the backup job has been adjusted, you may execute the program (FullBackup or IncrementalBackup).

In general, the task scheduler is used to execute the program on a regular basis. However, if you want to run a quick test, you may also execute the program manually. For this purpose, open the "Command Prompt" window. Change to the installation directory and enter the program name. CPTec Backup starts and executes the steps described in the following.

SwitchTarget

If a target is defined as a SwitchTarget, the target to be used actually will be determined first. The target in the list that has not been a backup target for the longest period of time will be selected. In the case of FullBackup, the <ExistingDateFolder ReuseSwitchTarget="yes/no" /> command can be used to specify if an already used target from the SwitchTarget list may be used again for another run on the same day. In the case of IncrementalBackup, the oldest target is always selected.

DateFolder

A DateFolder is created for each target. If the backup is started for the second time on the same day, the DateFolder may exist already. In this case, FullBackup and IncrementalBackup will react differently:

• IncrementalBackup will copy all modified files into the existing DateFolder. This means that all changes that have been made during the day will add up.
• FullBackup may delete either the entire DateFolder or only the currently affected SourceFolder in the DateFolder before the data are copied again. This behavior can be controlled by means of the <ExistingDateFolder DeleteBySource="yes/no"> command.

SourceFolder

One after the other, all sources are copied into the DateFolder. To this end, a SourceFolder with the name of the source is created for each source, and the data will be copied to this folder. <ArchiveBit Ignore="yes/no" Reset="yes/no" /> can be used to specify if all files or only modified files are copied and if the archive bit of the source files is reset after copying. <Security Copy="yes/no" /> can be used to specify if the access rights for the folders and files have to be copied too.

Automatic cleanup

If the free space on the target falls below the "FreeGB" value during the copy process, the software determines the oldest DateFolder on the target and deletes this folder. Afterwards the copying process is continued. If it is not possible to free enough disk space this way the backup is aborted.

Logging and messaging

During the copy process, two log files will be written into the folder specified with <LogFiles Path="Ordner" />: A "progress log" containing all files that have been copied and a "warning log" containing all files that could not be copied. The names of these log files start with the name of the DateFolder. The current state of the log files is copied into the DateFolder of each completed target.

Configuration errors are displayed in the console and in the event log. All other errors will be reported in the event log and via e-mail, if configured. Start and stop of the backup are also logged in the event log.

If configured, an e-mail containing statistical data and a copy of the warning log will be sent after the backup process has been completed.

Tips for efficient archiving

In general, sources are shared folders. In order to optimize efficiency, CPTec Backup performs the backup process in two steps: First, all sources are copied to the first target. Afterwards, the files are being copied from this target to all the other targets.

The benefits of this method become apparent if a local drive is selected for the first target. In this case, copying to the other targets offers the following advantages:

• Higher copying speed
• Reduced network load
• Reduced load on the source drives or servers
• Data on the different targets will be consistent

Version 1.0