|This section contains conceptual information about Tivoli Data Protection |for NDMP.
|Tivoli Data Protection for NDMP is not the only way to protect NAS file |servers using Tivoli Storage Manager, but it is recommended because it allows |the server to control operations while the NAS file server transfers the |data.
|Without Tivoli Data Protection for NDMP, you can back up a NAS file server |with a Tivoli Storage Manager backup-archive client. You mount the NAS |file server file system on the client machine (with either an NFS mount or a |CIFS map) and back it up as usual. However, there are some trade-offs |with this method: |
|With Tivoli Data Protection for NDMP: |
|Network-attached storage (NAS) file system images are the backups that are |stored when Tivoli Data Protection for NDMP backs up a NAS file server to a |SCSI-attached tape library. The image backups are different from |traditional Tivoli Storage Manager backups because the NAS file server (and |not the Tivoli Storage Manager server) transfers the data to the drives in the |library. | | |
|NAS file system image backups can be either full or differential image |backups. The first backup of a file system on a NAS file server is |always a full image backup. For subsequent backups, the default is a |differential image backup containing data that has changed in the file system |since the last full image backup. If a full image backup does not |already exist, a full image backup is performed.
|If you restore a differential image, Tivoli Storage Manager automatically |restores the full backup image first, followed by the differential |image. Tivoli Storage Manager cannot restore individual files from full |or differential image backups.
|The following operations are not supported for data that has been |backed up by using Tivoli Data Protection for NDMP: |
|You can use any of the interfaces described in this section to perform NDMP |operations. Only the Tivoli Storage Manager server interfaces support |scheduled NDMP operations.
|Client Interfaces: |
|Server Interfaces: |
|The Tivoli Storage Manager Web client interface, available with the Tivoli |Storage Manager backup-archive client, lets you display the file systems of |the NAS file server in a graphical view. The Tivoli Storage Manager |client function is not required, but you can use the client interfaces for |NDMP operations. Tivoli Storage Manager prompts you for an |administrator ID and password when you perform NDMP functions using either of |the client interfaces. See Tivoli Storage Manager Installing the |Clients for more information about installing and activating client |interfaces.
|The server interfaces allow you to perform and schedule NDMP operations by |using administrative commands at one of the server interfaces. All |examples in this chapter use the server command-line interface.
|Data movers and paths are Tivoli Storage Manager objects that are required |for NDMP operations. Data movers are named devices that accept requests |from Tivoli Storage Manager to transfer data. Characteristics of data |movers are that they transfer data: |
|For NDMP operations, Tivoli Storage Manager data movers represent NAS file |servers. The definition for a NAS data mover contains the network |address, authorization, and data formats required for NDMP operations. |A data mover enables communication and ensures authority for NDMP operations |between the Tivoli Storage Manager server and the NAS file server.
|Paths allow access to libraries or drives. Paths are defined with a |source and a destination, where the source is in a one-to-one relationship |with the destination. The source accesses the destination using a |particular device name, but data flows in either direction between the source |and destination.
|For example, in NDMP operations backup data flows across a path between the |source -- a data mover defined for a NAS file server -- and the |destination -- a tape drive. Restore data flows back across the |path from the tape drive to the NAS file server. Paths are used to |address the same destination device from different source devices. For |example, in NDMP operations, paths are always required between the data movers |that represent NAS file servers and the drives to which the file servers |transfer data for backup.
|The Tivoli Storage Manager server controls the library, but the NAS file |server controls the actual data format. This data format, for example |NETAPPDUMP for a Network Appliance device, is specified to Tivoli Storage |Manager when you define a data mover for a NAS file server and when you define |a storage pool that is used for NDMP operations. The NDMP format, which |is NETAPPDUMP for Network Appliance file servers, is not the same as the data |format used for traditional backups. Additional data formats will be |added as Tivoli Storage Manager adds support for NAS file servers from other |vendors.