Using the snapdiff option with the incremental command streamlines the incremental backup process. The command runs an incremental backup of the files that were reported as changed by NetApp instead of scanning all of the volume for changed files.
The snapdiff (snapshot difference) option is for backing up NAS/N-Series file server volumes that are NFS or CIFS attached.
You must configure a user ID and password on the Tivoli Storage Manager client to enable snapshot difference processing.
Use this option with an incremental backup of a NAS file server volume, instead of a simple incremental backup or an incremental backup with the snapshotroot option, whenever the NAS file server is running ONTAP 7.3.0, or later. Do not use the snapdiff and snapshotroot options together.
The first time that you run an incremental backup with the snapshot difference option, a snapshot is created (the base snapshot) and a traditional incremental backup is run by using this snapshot as the source. The name of the snapshot that is created is recorded in the Tivoli Storage Manager database. The initial incremental backup must complete without failure in order for the next backup operation to use snapshot difference processing.
The second time an incremental backup is run with this option, a newer snapshot is either created, or an existing one is used (depending on the value set for the diffsnapshot option) to find the differences between these two snapshots. The second snapshot is called the diffsnapshot, or differences snapshot. Tivoli Storage Manager then incrementally backs up the files that are reported as changed, by NetApp, to the Tivoli Storage Manager server. The file system that you select for snapshot difference processing must be mounted to the root of the volume. You cannot use the snapdiff option for any file system that is not mounted to the root of the volume. After you backed up the data with the snapdiff option, the snapshot that was used as the base snapshot is deleted from the snapshot directory.
On Windows systems, the snapshot directory is in ~snapshot.
On AIX and Linux systems, the snapshot directory is in .snapshot.
Tivoli Storage Manager does not delete any snapshots that it did not create.
When a snapshot-differential-incremental backup operation completes, Tivoli Storage Manager ensures that only the most recently-registered base snapshot persists on the filer volume. All snapshots that are created by a Tivoli Storage Manager snapshot-differential-incremental backup begin with the characters "TSM_". If you use a snapshot tool other than Tivoli Storage Manager to produce snapshots, ensure that you do not use the string "TSM_" at the beginning of the snapshot name. If the snapshot names begin with "TSM_", the files are deleted when Tivoli Storage Manager initiates the next snapshot-differential-incremental backup operation.
To run a snapshot-differential-incremental backup of read-only NetApp filer volumes, the useexistingbase option must be specified to prevent an attempt to create a snapshot on the read-only volume. Also, specify the name of the base snapshot to use (basesnapshotname option) and the name of the differential snapshot to use (diffsnapshotname option).
For NAS and N-Series file servers that are running ONTAP 7.3.0, or later, you can use the createnewbase option to back up any files that were skipped because of one of the following reasons:
Option | Where specified | With snapdiff |
---|---|---|
asnodename | Client system options file (dsm.sys) or command line. | Valid |
asnodename | Client options file (dsm.opt) or command line. | Valid |
automount | Client options file (dsm.opt). | No effect |
autofsrename | Client options file (dsm.opt) only. | No effect |
basesnapshotname | Client options file (dsm.opt) or command line. | Valid |
basesnapshotname | Client options file (dsm.opt) or command line. | Valid |
changingretries | Client system options file (dsm.sys) or command line. | No effect |
changingretries | Client options file (dsm.opt) or command line. | No effect |
compressalways | Client options file (dsm.opt) or command line. | Valid |
compressalways | Client options file (dsm.opt) or command line. | Valid |
compression | Client options file (dsm.opt) or command line. | Valid |
compression | Client system options file (dsm.sys) within a server stanza, or command line. | Valid |
createnewbase | Command line only. | Valid |
diffsnapshot | Command line only. | Valid |
diffsnapshotname | Client options file (dsm.opt) or command line. | Valid |
diffsnapshotname | Client options file (dsm.opt) or command line. | Valid |
dirsonly | Command line only. | Valid |
domain | Client options file (dsm.opt) or command line only. | Valid |
domain | Client system options file (dsm.sys), client user-options file (dsm.opt), or command line. | Valid |
efsdecrypt | Client system options file (dsm.sys), client user-options file (dsm.opt), or command line. | No effect |
enablelanfree | Client system options file (dsm.sys) or command line. | Valid |
enablelanfree | Client options file (dsm.opt) or command line. | Valid |
encryptiontype | system-options file (dsm.sys) within a server stanza. | Valid |
encryptiontype | Client options file (dsm.opt). | Valid |
encryptkey | Client options file (dsm.opt). | Valid |
encryptkey | System-options file (dsm.sys) within a server stanza. | Valid |
exclude.fs.nas | Client system options file (dsm.sys). | No effect |
exclude.fs.nas | Client options file (dsm.opt). | No effect |
filelist | Command line only. | Not valid |
filesonly | Command line only. | Valid |
followsymboliclink | Client options file (dsm.opt). | No effect |
include.fs.nas | Client system options file (dsm.sys) or command line. | No effect |
include.fs.nas | Client options file (dsm.opt) or command line. | No effect |
inclexcl | Client system options file (dsm.sys). | Valid, but only when a file change is detected by NetApp. |
inclexcl | Client options file (dsm.opt). | Valid, but only when a file change is detected by NetApp. |
incrbydate | Command line only. | Not valid |
memoryefficientbackup | Client options file (dsm.opt), server, or command line. | No effect |
memoryefficientbackup | This option is allowed in both dsm.sys and dsm.opt, but the value in dsm.opt is ignored if it is also in dsm.sys. You can also place this option within a server stanza, or on the initial command line. | No effect |
monitor | Command line only. | Not valid |
nojournal | Command line only. | Not valid |
nojournal | Command line only. | Not valid |
postsnapshotcmd | Client system options file (dsm.sys) or with the include.fs option. | Valid |
postsnapshotcmd | Client options file (dsm.opt) or with the include.fs option. | Valid |
preservelastaccessdate |
Client user-options file (dsm.opt) or command line. | Valid |
preservelastaccessdate | Client options file (dsm.opt) or command line. | Valid |
presnapshotcmd | Client system options file (dsm.sys) or with the include.fs option. | Valid |
presnapshotcmd | Client options file (dsm.opt) or with the include.fs option. | Valid |
removeoperandlimit | Command line only. | Valid |
resetarchiveattribute | Client options file (dsm.opt). | Valid |
skipaclupdatecheck | Client options file (dsm.opt). | Valid |
skipntpermissions | Client options file (dsm.opt) or command line. | Valid |
skipntsecuritycrc | Client options file (dsm.opt) or command line. | Valid |
snapdiffhttps | Command line only. | Valid |
snapshotcachesize | Client system options file (dsm.sys) or with the include.fs option. | No effect |
snapshotproviderfs | System-options file (dsm.sys) within a server stanza or with the include.fs option. | Not valid |
snapshotproviderfs | Client options file (dsm.opt) or with the include.fs option. | Not valid |
snapshotproviderimage | Client system options file (dsm.sys) or with the include.image option. | Not valid |
snapshotproviderimage | Client options file (dsm.opt) or with the include.image option. | Not valid |
snapshotroot | Command line only. | Not valid |
subdir | Client options file (dsm.opt) or command line. | Not valid |
subfilebackup | Client options file (dsm.opt) or command line. | Not valid |
tapeprompt | Client options file (dsm.opt) or command line. | Valid |
tapeprompt | Client options file (dsm.opt) or command line. | Valid |
toc | Command line only. | Not valid |
toc | Command line only. | Not valid |
useexistingbase | Command line only. | Valid |
useexistingbase | Command line only. | Valid |
virtualfsname | Command line only. | Not valid |
virtualmountpoint | Client system options file (dsm.sys). | Not valid |
There are no parameters for this option.
dsmc incremental -snapdiff -createnewbase=migrate /net/home1
dsmc incremental -snapdiff -createnewbase=migrate h:
dsmc incremental -snapdiff -createnewbase=ign /net/home1
dsmc incremental -snapdiff -createnewbase=ign h:
dsmc incremental -snapdiff -createnewbase=yes /net/home1
dsmc incremental -snapdiff -createnewbase=yes h: