See NetBackup Commands Reference Guide About reading and writing tape files

See netbackup commands reference guide about reading

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See NetBackup Commands Reference Guide . About reading and writing tape files Reading or writing tape files involves copying the file from tape to disk or from disk to tape. To perform read or write operations, use one of the UNIX commands that performs input and output operations, for example tar or mt . The mt command positions tape files by skipping forward or backward according to tape marks. The following options are available on the mt command for positioning tapes: eof, weof Writes an end-of-file tape mark at the current position on the tape according to the count option on mt . fsf, bsf Spaces forward or backward the number of tape marks on the count option. fsr, bsr Spaces forward and backward the number of records according to the count option on mt. bsr is only supported for the undefined record type. The following example uses the mt command to skip forward three files on a tape: mt -f tape1 fsf 3 Positioning tape files When a file is rewound, it is positioned to the beginning of the data. To rewind a tape file, you can use the mt command. tape1 is positioned to the beginning of the tape volume that is associated with the file. The following command rewinds file tape1 : mt -f tape1 rewind The count option is not used for the rewind operation. If you specify a count, mt ignores it. Rewinding tape files 211 Reference topics About Tape I/O commands on UNIX
About removing tape files When you have completed reading or writing tape files, use the /usr/openv/volmgr/bin/tpunmount command to end the assignment of the tape file. This command removes from the directory the tape file you created by using tpreq and removes the tape volume from the tape drive. The tpunmount command is required for each file that the tpreq command creates. See NetBackup Commands Reference Guide . On UNIX, the NetBackup tpunmount command runs the drive_unmount_notify script (if it exists) after media is unmounted. See “drive_unmount_notify script (on UNIX)” on page 170. About external access to NetBackup controlled devices on UNIX The Media Manager device daemon ltid restricts access to drives that are in an UP state by changing the permissions of the device files for those drives. The permissions are changed to 0600 when ltid starts and back to their original settings when ltid is terminated. The permissions also are returned to their original settings when a drive’s state is changed to DOWN ). Do not modify the permissions of these device files when ltid is active. The NetBackup avrd daemon periodically tries to rewind and read data from media in the drives that are UP and are not currently assigned in NetBackup. To ensure reliable operation, do not use UNIX tape and drive commands on the drives that are UP and controlled by ltid . Users can use the NetBackup tpreq and tpunmount commands and the drive_mount_notify and drive_unmount_notify scripts on those drives.

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