In the remote NDMP scenario, there are no Fibre Channel connectors present in the cluster. Instead, the DMA uses NDMP over the LAN to instruct the cluster to start backing up data to the tape server—either connected by Ethernet or directly attached to the DMA host. In this model, the DMA also acts as the Backup/Media Server.
During the backup, file history is transferred from the cluster over NDMP over the LAN to the backup server, where it is maintained in a catalog. In some cases, the backup application and the tape server software both reside on the same physical machine.
OneFS remote NDMP backup also includes intelligent IP selection functionality. This enables backup applications like Avamar and Commvault to select the most desirable interfaces and preferred network for NDMP traffic.
OneFS accommodates the range of full, incremental and token-based backups. In standard DR nomenclature, Level 0 indicates a full backup, and levels 1 to 9 are incrementals. Any level specified as 1 to 9 will back up all the files that have been modified since the previous lower-level backup.
Token-based incremental backups are also supported. These are achieved by configuring the data management application (DMA) to maintain a timestamp database and to pass the reference time token on to the cluster for use during each incremental backup. This method does not rely on level based incremental backups, as described above, at all.
OneFS provides full supports for Direct Access Recovery (DAR). Direct Access Recovery allows the NDMP server to go directly to the location of a file within an archive and quickly recover that file. As such, it eliminates the need to scan through vast quantities of data typically spread across multiple tapes in an archive set, in order to recover a single file. This capability uses the offset information that is contained in the file history data passed to the DMA at backup time.
OneFS NDMP also supports Directory DAR (DDAR), an extension of DAR. DDAR allows the NDMP server to go directly to the location of a directory within an archive and quickly recover all files/directories contained within the directory tree hierarchy. Clearly, both DAR and DDAR provide an improved RTO for smaller scale data recovery from tape.
OneFS NDMP offers Selective File Recovery—the ability to recovering a subset of files within a backup archive. Also supported is the ability to restore to alternate path locations.