Installation and User's Guide

Snapdiff||||Using the snapdiff option with the incremental command streamlines theincremental backup process. The command runs an incremental backup of the filesthat were reported as changed by NetApp instead of scanning all of the volumefor changed files.The snapdiff option is for backing up NAS/N-Series file server volumes that areNFS or CIFS attached.Restriction: None of the NetApp predefined shares, including C$, works with theTivoli Storage Manager snapshot difference option because Tivoli Storage Managerclient cannot determine their mount points programmatically.You must configure a user ID and password on the Tivoli Storage Manager clientto enable snapshot difference processing. For more information about setting upthe snapdiff option, see “Configuring the file server connection for Tivoli StorageManager” on page 64.Use this option with an incremental backup of a NAS file server volume instead ofa simple incremental or incremental with snapshotroot whenever the NAS fileserver is running ONTAP 7.3.0, or later, for performance reasons. Do not use thesnapdiff and snapshotroot options together.The first time you perform an incremental backup with the snapshot differenceoption, a snapshot is created (the base snapshot) and a traditional incrementalbackup is run using this snapshot as the source. The name of the snapshot that iscreated is recorded in the Tivoli Storage Manager database.The second time an incremental backup is run with this option, a newer snapshotis either created, or an existing one is used to find the differences between thesetwo snapshots. The second snapshot is called the diffsnapshot. Tivoli StorageManager then incrementally backs up the files reported as changed by NetApp tothe Tivoli Storage Manager server. The filesystem that you select for snapshotdifference processing must be mounted to the root of the volume. You cannot usethe snapdiff option for any filesystem that is not mounted to the root of thevolume. After backing up data using the snapdiff option, the snapshot that wasused as the base snapshot is deleted from the .snapshot directory. Tivoli StorageManager does not delete the snapshot if it was not created by Tivoli StorageManager. You can also run a snapshot-difference incremental-backup by specifyingthe -diffsnapshot=latest option.|||For NAS and N-Series file servers that are running ONTAP 7.3.0, or later, you canuse the createnewbase option to backup any files that might have been skippeddue to one of the following reasons:vvvA file is excluded because the include-exclude file has an exclude rule in effect.A file is excluded when you have not changed the include-exclude file, but youhave removed the rule that excluded the file. The NetApp API only detects filechanges between two snapshots, not changes to the include-exclude file.If you have added an include statement to the option file, that include optiondoes not take effect unless NetApp detects that the file has changed. This isbecause Tivoli Storage Manager does not inspect each file on the volume duringbackup.You have used the dsmc delete backup command to explicitly delete a file fromthe Tivoli Storage Manager inventory. NetApp does not detect that a file has464 IBM Tivoli Storage Manager for Windows Backup-Archive Clients: Installation and User's Guide