La formación del instrumento y las pruebas piloto

played. If you chose to just view the files in the backup, the page will display a list pro- duced 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.

14.7 Configuring the Filesystem Backup Module

Clicking on the Module Config link in the top-left corner of this module’s main page will bring up a form for setting options that control how it behaves. The available settings and their mean- ings are see in Table 14.1.

Configuring the Filesystem Backup Module 127

Figure 14.3 The backup restoration form.

Table 14.1 Module Configuration Options

Do strftime substitution of backup destinations?

If Yes is selected in this field, the backup destination path will have any special codes starting with % replaced with components of the current time and date. For example, %m will be replaced with month number, %d with the day of the month and %y with the year. These are the same substations that the standard UNIX strftime function uses. This option is useful if you want the backup to be written to a different file each day, instead of over-writing the same file every time. The default option is No, which turns off this behavior.

Send mail via SMTP server When Local sendmail executable is selected, the output from scheduled backups will be sent by running the sendmail com- mand on your system, the path to which is taken from the Sendmail Configuration module. However, you can tell the module to send email by making an SMTP connection to some other host instead, which may be necessary if your system does not run a mail server at all, or runs one other that Sendmail. Just select the second radio button and enter a hostname into the text box.

14.8 Other Operating Systems

Many UNIX operating systems have similar dump and restore commands to Linux, and several of them are supported by this Webmin module. However, the options available differ slightly, so the backup and restore forms on different systems will not be exactly the same as Linux.

The currently supported systems and their differences are:

Sun Solaris On Solaris, ufs filesystems can be backed up and restored using the

ufsdump and ufsrestore commands. When creating a backup, the Split across

multiple files? and Tape size options are not available—instead, there are Verify data after backup? and Eject tape after backup? options whose meanings should be obvious. Solaris also supports the backing up of multiple directories at once, by entering multiple paths separated by spaces into the Directory to backup field. For restoring on Solaris, the options are essentially the same as on Linux.

FreeBSD and Apple MacOS X Both these operating systems have almost identical dump commands and available options in Webmin, due to the BSD ancestry of MacOS X. When making a backup, the Split across multiple files? and Dump label fields are not available, but Tape size is. The only filesystem type that can be backed up is ufs and a backup must be of an entire filesystem, not just any directory. Unfortunately, on MacOS X almost all filesystems are in Apple’s native

hfs format.

When restoring, the only difference is an additional Just test backup? option which when set causes the restore command to do everything except write to disk.

SGI Irix On Irix, the only filesystem type that can be backed up with Webmin is

xfs, even though there is a dump command for older efs filesystems. As with the

xfs filesystem on Linux, only entire filesystems can be backed up, not arbitrary directories. The Tape size option is not available, but instead you can limit the size of files to include with the Maximum file size to include option, and turn off the backing up of attributes with the Include file attributes? option.

When restoring a backup on Irix, there is no option to specify which files to extract—instead, everything in the backup will be restored. However, there is an Overwrite existing files? option to protect existing files, or existing files that are newer than the backup, from being overwritten.

Due to the low-level nature of backups made using the dump family of commands, a backup cre- ated on one operating system will not be restorable on any other.

14.9 Summary

After reading this chapter, you should be able to use Webmin to create backups of data on your system’s local hard disks, and restore those backups if needed. You should also understand the difference between the dump backup format used by the module covered here, and those created by commands like tar and cpio. On a system running important servers or hosting vital data, proper backups are vital—and Webmin can help you create them.

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