Backup Volume Options
You can set up your system to utilize a second volume to backup DICOM objects for your primary one. Various options are available as described in the following table:
| Primary Volume | Secondary Volume |
|---|---|
| Azure | Azure |
| Azure | On-Premises |
| On-Premises | Azure |
| On-Premises | On-Premises |
To enable this backup process, you need to define the backup volume in the maintenance module. Besides, there are setting in PowerReader that should be configured.
Setting up the Backup Volume
A new or existing volume (Setting Up Disk Volume) would be used as the destination for the backup process. Based on the volume type, and to ensure that this volume does not interfere with regular object writing, make sure to fulfill this requirement:
- Disk Volume: it should be fully reserved
- Azure Blob Volume: it should be read-only
PowerReader Configurations
To access these settings, open PowerReader and go to Settings menu | System Configurations:
| System Configuration Variable | Required setting |
|---|---|
| Object Backup Enabled | check to enable |
| Object Backup Volume ID | Volume ID (defined in maintenance module) |
| Object Backup Number of Workers (default is 8) | The number of threads used to backup all objects, increase the default if you want to allocate more system resources to this task. |
| Object Backup Max Records (default is 50000) | The number of records that will be queried from the database at once when assigning objects to workers to be backed up. |
| Object Backup Timer Interval (default is 60000 ms) | Timer interval at which the backup process will restart after completing a backup session (if it is not still running). This is used to include new objects that added from the last time that the backup process started. |
| Object Backup Last SOP Instance UID | Used to track the progress of a backup session from start to finish. If the process is reset, it will start at this point. |
How the backup process works
Requirement: Object Backup Enabled is true and Object Backup Volume ID is valid (i.e. volume that exists and is fully reserved.)
On startup, the system will look at existing DICOM objects and if there is any discrepancy with the backup volume (Object addition, deletion), it will update the backup volume. The backup process keeps track of its progress via the Object Backup Last SOP Instance UID config entry (explained above), which will be cleared when completed.
On predefined intervals (default is 60 seconds), the backup process will start again if not already running. This will allow the backup process to backup objects that had not yet arrived when the process was previously executed. During backup, as well as migration, the system verifies all uploads and downloads via MD5 hash checking to ensure that no file corruption happens.