After successfully backing up files using NDMP, you can perform a restore of files from the NDMP backup. OneFS NDMP supports full restore, selective file restore, DAR, and DDAR.
- Full restore: The full restore process reads all data across multiple tapes to restore all data to the chosen location. A full restore typically takes a painfully long time to complete. If only a subset of files in the backup needs to be restored, the full restore is inefficient.
- Selective file restore: This feature can restore independent files of the backup without having to restore all files in the backup. During a selective file or files restore, the restore process reads from the beginning of the backup tape until it locates the file or files. Then the process restores it to the chosen location.
- DAR: DAR provides DMA with positioning information of a file on tape. It allows the NDMP server to go directly to the location of that file on tape and restore that file. DAR can significantly reduce the restoration time for an individual file restoration.
- DDAR: DDAR is an extension of DAR. DAR provides DMA with positioning information of a directory on tape. It allows the NDMP server to go directly to the location of that directory on tape and restore that directory. DDAR can significantly reduce the restoration time for an individual directory restoration.
Run the following command to check the restore type (OP) of the running NDMP session.
# isi ndmp sessions list
For the completed NDMP session, you can check the restore type (DIRECT) through the logs at /ifs/.ifsvar/modules/ndmp/trace.
The following are examples of NDMP restore type indicated through the above command or logs.
R(F): Full restore
R(S): Selective restore