Summary
Catalogic Software Advanced Protection Manager and Open Storage Server (OSS) backups are performed at the block level. As such, any changes that occur at the block level that are not captured by the DPX software may result in unusable backup data. Such changes could be caused by utilities such as chkdsk.
Symptoms
Running incremental Advanced Protection Manager or OSS backups after running chkdsk may result in unusable backup data
Resolution
In the event that data is changed at the block level outside of normal operating conditions, a user initiated new base backup must be performed to ensure data integrity on all future backups. As such, Catalogic Software recommends running chkdsk prior to running the initial base backup to prevent having to run a second base backup in the scenario where an undetected and uncorrected condition exists prior to running the first base backup.
At any time after running chkdsk to correct problems or performing any other block level change not captured by the Catalogic Software snapshot agent, a user initiated new base backup must be performed to ensure data integrity on all future backups.
Catalogic Software has created a utility (BEXCHKDSK) that performs the chkdsk process and prepares the volume that was repaired so that a base backup will automatically run the next time the scheduled backup occurs. All parameters that are available with the standard chkdsk utility (as described in the Microsoft documentation referenced below) can be used with the Catalogic Software provided utility. BEXCHKDSK is the preferred utility for repairing damaged volumes once a server has been backed up using the APM or OSS block level backup facility to avoid the possibility of unusable backup data.
An example of the utility being run on the boot volume of a node:
The utility will issue a warning that a base backup will run after the volume is repaired. In this example the volume was the boot volume, chkdsk will be run the next time the server is rebooted. In the case of a non-boot volume, chkdsk will be run immediately and the volume will be prepared for a fresh base backup after the repair has completed.
The BEXCHKDSK utility can be downloaded from our Catalogic Software Online Customer Support location:
mysupport.catalogicsoftware.com