How does NDMP image restore handle smaller and larger target mail stores?
NOTE: Before reading this article, Mirapoint highly recommends reading the latest version of the Mirapoint Backup and Restore Guide..
When performing an NDMP image restore to an appliance with a larger mail store then the original, either because arrays have been added or replaced, the restored mail store is grown to make use of all available space.
If the target mail store is smaller, because not all available arrays have been configured or because of how one got to the currently installed MOS version, the image restore attempts to find enough space in other partitions on the appliance.
If enough additional space cannot be configured, the restore does not run. If this occurs, use the Storage Configure command to manually configure additional space as needed.
Once the restore completes, the restored mail store is checked. If valid, it is then shrunk to fit into the space available. If the store is not valid or if there was not enough free space to shrink into, the restore fails.
The space required to restore an image backup is based on the size of the mail store being backed up, not the amount of data on that mail store. This is because a partition layout is backed up, not file-based data. To determine the total size required for backup, use the Storage Space command. For example:
mail.system.com> storage space
The first number in the output from the Storage Space command, total size, is the number to be use for comparison.
The size of an appliance mail store can also vary based on how the appliance got to its currently installed MOS. For example, if your appliance was at 3.5 and you installed patches or releases to reach 3.8, your mail store is larger than if you performed a disaster recovery of 3.8 on that appliance.
NOTE: Currently, the check and shrink are performed before informing the NDMP client that the Mirapoint appliance is finished restoring the data stream. This can cause some clients to time out and erroneously claim that the restore failed.
Backup solutions are not available on the RazorGate family of appliances.