Installation and User's Guide

vvIndividual server attributes are not available during a journal-basedbackup. Certain policy settings such as copy frequency and copy modemight not be enforced.Other platform-specific behaviors might prevent objects from beingprocessed properly. Other software that changes the default behavior ofthe file system might prevent file system changes from being detected.v If the file system is very active when a journal-based backup is inprogress, it is possible that a small number of deleted files will not beexpired.The memory requirements for subsequent journal-based backups are muchless. Journal backup sessions run in parallel and are governed by theresourceutilization client option in the same manner as normal backupsessions. The size of the journal database file reverts to a minimal size (lessthan 1 K) when the last entry has been deleted from the journal. Sinceentries are deleted from the journal as they are processed by the client, thedisk size occupied by the journal should be minimal after a completejournal backup. A full incremental backup with journaling active takes lesstime to process than an incremental-by-date backup.NetApp snapshot differenceAn incremental-by-date backup might not place exactly the same backupfiles into server storage because the incremental-by-date backup:vvvDoes not expire backup versions of files that you delete from theworkstation.Does not rebind backup versions to a new management class if youchange the management class.Does not back up files with attributes that change, unless themodification dates and times also change.v Ignores the copy group frequency attribute of management classes(Journal-based backups also ignore this attribute).For NAS and N-Series file servers that are running ONTAP 7.3.0, or later,you can use the snapdiff option to invoke the snapshot difference backupfrom NetApp when running a full-volume incremental backup. Using thisoption reduces memory usage and is faster.Consider the following restrictions when running a full-volumeincremental backup using the snapdiff option, to ensure that data is backedup when it should be.vvvA file is excluded due to an exclude rule in the include-exclude file.Tivoli Storage Manager runs a backup of the current snapshot with thatexclude rule in effect. This happens when you have not made changes tothe file, but you have removed the rule that excluded the file. NetAppwill not detect this include-exclude change because it only detects filechanges between two snapshots.If you added an include statement to the option file, that include optiondoes not take effect unless NetApp detects that the file has changed.Tivoli Storage Manager does not inspect every file on the volume duringbackup.If you used the dsmc delete backup command to explicitly delete a filefrom the Tivoli Storage Manager inventory, NetApp cannot detect that afile was manually deleted from Tivoli Storage Manager. Therefore, thefile remains unprotected in Tivoli Storage Manager storage until it isChapter 4. Backing up your data 117