Creating Consistent Point-in-Time Backups

Some programs may write some data on the disk while R-Drive Image is creating a data backup. To avoid data inconsistency, R-Drive Image uses two mechanisms for creating consistent point-in-time backups.

R-Drive Image uses Microsoft Volume Shadow Copy Service (VSS) to notify other applications supporting this service that it is going to start a data backup process in order for them to flash all necessary data to the disk. Most applications like Microsoft Exchange Server, Microsoft SQL Server, and Oracle software support this service.

Options Windows Volume Snapshot Service and Notify system application on the Backup Options panel enable/disable the use of this service.

If a software that does not support VSS runs on your computer, you may use Backup AUX applications and Snapshot AUX applications on the Backup Options panel (and their respective commands/parameters in scripts) to send special commands to your application that will make that application flush its data to the disk before the backup process starts.

R-Drive Image uses its own driver to create a file system snapshot but it does not notify other applications that it is going to start a backup process. Therefore, if an application stores some of its data in memory, they will not be saved in the backup file. To avoid data inconsistency, we recommend you to use Backup AUX applications and Snapshot AUX applications on the Backup Options panel (and their respective commands/parameters in scripts) to send special commands to your application that will make that application flush its data to the disk before the backup process starts.

Option R-TT Volume Snapshot Service on the Backup Options panel enables/disables the use of this service.

Snapshot provider	A snapshot provider is a service R-Drive Image uses to read the disk content while creating its image. R-Drive Image uses the snapshot providers in the order specified on the tab. If it fails to use the first one selected, it tries to use the second one, and so on.
Windows Volume Snapshot Service	If this check box is selected, R-Drive Image will try to use the Windows native snapshot provider. This snapshot provider is able to notify system applications that a snapshot is being taken. If this option is selected, pagefile.sys and hibernate.sys files are excluded from the image of the system disk.
R-TT Volume Snapshot Service	If this check box is selected, R-Drive Image will try to use R-TT snapshot provider. This snapshot provider is not able to notify system applications that a snapshot is being taken.
Notify system applications	If this check box is selected, the snapshot provider, if it supports this feature, notifies system applications that a snapshot is being taken.
Ignore disk read errors (bad sectors)	If this check box is selected, will ignore possible read errors when it tries to read data from bad sectors
Backup AUX applications	R-Drive Image is able to make applications run before and after all backup operations. Please note that those application should return a 0 exit code. Leave these fields blank if in doubt.
Before	An application R-Drive Image starts before the backup operations starts. If you need to start several application, you may use a command file. Example: "cmd.exe /c example.bat"
After	An application R-Drive Image starts after the backup operations completes. If you need to start several application, you may use a command file. "cmd.exe /c example.bat"
Snapshot AUX applications	R-Drive Image is able to make applications run before and after taking the snapshot of one or several volumes. Please note that those application should return a 0 exit code. Leave these fields blank if in doubt.
Before	An application R-Drive Image starts before it takes the snapshot of one or several volumes. If you need to start several application, you may use a command file. "cmd.exe /c example.bat"
After	An application R-Drive Image starts after it takes the snapshot of one or several volumes. If you need to start several application, you may use a command file. "cmd.exe /c example.bat"
Save as default	Click this button to make the current settings default.
Reset	Click this button to reset the current settings default.
Restore defaults	Click this button to restore default settings.

If any of Backup AUX applications and Snapshot AUX applications are executed, the following environment variables are set:

R_CALLBACK_UID	A unique digital backup id used in all calls for external commands pertaining to that backup process.
R_CALLBACK_STAGE	Takes the following values: BEFORE_BACKUP AFTER_BACKUP BEFORE_SNAPSHOT AFTER_SNAPSHOT
R_VOLUME_NAMES	A comma-separated name list of partitions to be processed.
R_VOLUME_GUIDS	A comma-separated GUID list of partitions to be processed

Therefore, the same command may be used for all the fields provided it will determine using R_CALLBACK_STAGE in which context it is called.

R_VOLUME_GUIDS={d5f570a1-2978-11dc-83bf-005056c00008},{9636e065-f75e-11dc-981a-829328f78201}

Note: If the system settings permit, several disks may appear in one snapshot. Then the following calls will appear:

R_VOLUME_GUIDS={d5f570a1-2978-11dc-83bf-005056c00008},{9636e065-f75e-11dc-981a-829328f78201}