14.6. Restoring a Backup
Backups made using Webmin (or by running the dump command manually) can be restored using this module as well. If you have been creating backups of different levels, they must be restored in ascending level order starting with the complete backup (level 0). A backup can be restored to any directory, not just the one that it was originally saved from. However, some file information such as ACLs and attributes will be lost if the restore directory's filesystem does not support them.
To restore a backup, the steps to follow are:
1. | On the main page of the Filesystem Backup module, select the type of filesystem that the backup was made from, using the list next to the Restore backup of filesystem type button. Because there are different programs for restoring different types of filesystems, the restore options will vary depending on the type you choose. |
2. | Click the Restore backup of filesystem type button, which will take you to the restore options page. Figure 14.3 shows the page for restoring an ext2 or ext3 filesystem backup. Figure 14.3. The backup restoration form.
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3. | If restoring from a local file, set the Restore from file or device field to the File or tape device option and enter the file that you want the backup read from into the text field next to it. Restoring from a tape drive is similar to reading from a file, but instead of entering a filename into the File or tape device field you must enter the device file for the tape drive: /dev/st0, for example. If restoring from another server, you must select the Host option and enter a hostname, remote username, and file or device name on the remote server. As explained in Section 14.3 “Adding a New Backup”, the server must have been configured correctly to allow remote access. |
4. | By default, everything in the backup will be restored. To extract only some files, set the Files to restore option to Listed files and enter paths to the files you want to restore into the field next to it. To restore multiple files, the filenames must be separated by spaces. Because the paths used in the backup are sometimes relative to the mount point of the filesystem that they were originally on, it is often a good idea to use the Only show files in backup? option to see what the correct filenames are. |
5. | In the Restore to directory field, enter the base directory under which you want the restored files to be saved. |
6. | If the original backup spanned multiple files, set the Backup is split across multiple files? option to Yes. |
7. | If you just want to view the contents of the backup without extracting any files, set the Only show files in backup? option to Yes. |
8. | |
9. | When you are ready to restore, click the Restore Backup Now button. If extracting files for real, a page showing the output of the appropriate restore command will be displayed. If you chose to just view the files in the backup, the page will display a list produced by the restore command instead. |
When restoring a backup from an xfs filesystem, different options are available on the restore form. The Files to restore option does not exist, so all files in the backup will be extracted. However, there is an Overwrite existing files option that can be set to Never to protect existing files, or Unless newer than backup to protect files that have been modified since the backup was made.
One problem with using Webmin to restore is that it cannot cope with backups that span multiple tapes. Normally the restore command would prompt the user to eject the first tape and insert the second, but that is not possible when it is being run by Webmin.