The dump engine enables you to recover all the information that you backed up.
The dump engine can recover the following data:
- Contents of files and directories
- UNIX file permissions
If you restore a file that has only UNIX file permissions into an NTFS qtree or volume, the file has no Windows NT ACLs. The storage system
uses only the UNIX file permissions on this file until you create a Windows NT ACL on it.
Attention: Data ONTAP 7.3 and later releases support more than 192 Access Control Entries (ACEs) per ACL, whereas earlier versions support only a maximum of 192. Therefore, any data migration from Data ONTAP 7.3 or later releases to an earlier release will result in loss of ACLs.
Note: If you restore ACLs backed up from storage systems running Data ONTAP 8.2 to storage systems running Data ONTAP 8.1.x and earlier that have an ACE limit lower than 1024, a default ACL is restored.
- Qtree information
Qtree information is used only if a qtree is restored to the root of a volume. Qtree information is not used if a qtree is restored to a lower directory, such as /vs1/vol1/subdir/lowerdir, and it ceases to be a qtree.
- All other file and directory attributes
- Windows NT streams
- A LUN must be restored to a volume level or a qtree level for it to remain as a LUN. If it is restored to a directory, it is restored as a file because it does not contain any valid metadata.
- Clustered Data ONTAP volume can be restored to a 7-Mode volume.
- SnapLock volumes are restored as normal read/write volumes.
- The destination volume for a restore operation might have files with mandatory or advisory locks. While performing restore operation to such a destination volume, the dump engine ignores these locks.
You can restore data from previous versions of Data ONTAP using the dump engine. If you want to perform an incremental restore to a storage system running Data ONTAP 6.2 or later using data backed up from a storage system running a version of Data ONTAP earlier than 6.2, you can do one of the following:
- You must perform a level 0 restore and incremental restores before you upgrade to Data ONTAP 6.2 or later.
- You must perform a level 0 restore and incremental restores after you upgrade to Data ONTAP 6.2 or later.
Performing a level 0 restore, upgrading Data ONTAP software, and then performing incremental restores will not restore the incremental backups because the data is in a different format from the level 0 restore. In such a case, you have to repeat the level 0 restore before you can restore incremental backups.