The dump command writes file system data from disk to tape in a format that enables you to restore the data to a filer using the filer's restore command or the Solaris ufsrestore command.
The dump command can back up a file, a directory, a qtree, or an entire volume. In the dump command, you specify the complete path name to be backed up. In this chapter, this path name is referred to as the "dump path."
The dump path can exist in the filer's active file system or in a snapshot. If the dump path is in an active file system, the filer takes a snapshot of the active file system before it writes the data to tape. The snapshot capability ensures that the data written to tape is consistent. As a result, you need not take the filer or volume off-line before initiating the backup.
The dump command names each snapshot it creates snapshot_for_backup.n. The n at the end of the snapshot name is an integer starting at 0. Each time the dump command creates a snapshot, it increments the integer by 1. The filer resets the integer to 0 when it is rebooted.
The dump command automatically deletes the snapshot after it successfully finishes the backup.
When the filer executes multiple dump commands simultaneously, the dump commands create multiple snapshots. For example, if the filer is running two dump commands simultaneously, you find these snapshots in the volumes from which data is being backed up: snapshot_for_backup.0 and snapshot_for_backup.1.
Caution: When the dump command is in progress, the filer does not allow you to delete the snapshot_for_backup.n file. If you are backing up data from an hourly, daily, or weekly snapshot, make sure that the snapshot scheduler does not delete the snapshot before the dump command is finished.
In addition to backing up data within files, the dump command backs up these types of metadata:
Note: The CIFS attributes (DOS name, attributes, and create time, and Windows NT ACLs) can be restored only with the filer's restore command. You cannot use the Solaris ufsrestore command to restore these attributes, although the ufsrestore command can restore the data in CIFS-created files.
Options in the dump command enable you to exclude certain types of data from the backup.
You can choose not to back up Windows NT ACLs if the data is used only by NFS clients.
You can choose to exclude files and directories from a backup if you do not need those files and directories again. For example, you can exclude temporary files generated by some applications or object files produced during program compilation.
When the dump command traverses the dump path, it compares file and directory names to each exclude string specified in the dump command. If the name exactly matches the string, the file is excluded from the backup.
Note: You can reduce the amount of backup data by using an exclude list in the dump command. However, an exclude list increases the amount of time needed to finish a dump command because the filer must compare each file name to the exclude list to determine whether the file should be backed up.
The dump command can back up data to these devices:
You can specify the level of backup in a dump command ("dump level"), which ranges from level 0 to level 9. A level 0 backup is a full backup: It writes all data in the dump path to the backup media. Backups at dump level ranging from level 1 to level 9 are incremental backups. In an incremental backup, only files changed since the previous level are written to the backup media.
You can enter the dump command through the console or through rsh.
Entering the dump command through rsh gives you these benefits:
If you enter the dump command on the console, you can read and respond to screen messages displayed by the command. For example, the command might prompt you for another tape to complete the backup. A dump command entered through rsh aborts and does not generate any messages when the command needs user intervention.
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Part No. 210-02334
File: dump1.htm
Last updated: 04/26/99 08:11:48