Section 11.8. Automate Bare-Metal Recovery with G4L

11.8. Automate Bare-Metal Recovery with G4L

Now that we've discussed how to back up machines using a Linux boot disk, there is an easier solution that some users may find to their liking. G4L is a bootable CD-ROM that provides a menu-based system that automates making all the alternate-boot bare-metal backups we covered earlier. G4L is a freeware tool currently based on a 2.6 Linux kernel. It includes dd, ntfsclone, and tar but does not include mount, so backups to another host are done using FTP.

G4L is an abbreviation for Ghost 4 Linux, but do not confuse it with another project by that name. G4L does not use Norton Ghost and uses the term ghost only in a generic sense; it was used long before Norton created its brand. The other project that you will find if you search the Internet for the phrase "Ghost4Linux" uses a network boot of Linux to run a simulated DOS environment that can run some versions of Norton Ghost. That is not how G4L works; it is its own complete utility.

11.8.1. Advantages of G4L

G4L is much easier to use than the method outlined in this chapter. For most users, no Linux knowledge is needed. Since FTP is a much more efficient way to transfer data than NFS or CIFS, it is typically 20 to 30 percent faster. Because G4L uses FTP, Windows-only environments can easily set up an IIS FTP server to store the backup images. G4L can automatically compress the backup in stream, using light to heavy compression to improve backup speed. It also provides easy disk-to-disk duplication support. It supports SAN devices and can be used to do disk-to-disk backups. G4L also includes the dd_rhelp and dd_rescue utilities to recover a disk with bad sectors. G4L runs as a Microsoft Virtual PC Machine, so you can test it out in a safe environment.

11.8.2. Drawbacks of G4L

G4L does have some limitations. Since it is a Linux-based imaging solution, it may not have driver support for some hardware. It can only do backups over the network using FTP. It does not currently support NFS or SMB/CIFS mounts. Even though it is simple and fairly intuitive, its documentation is currently not as good as it could be. Hopefully, that will improve.

11.8.3. Setting Up G4L

Setting up G4L is very easy. Since you are backing up using FTP, you need an FTP server. This can be done easily using IIS, war-ftpd, or any other FTP server that you like. You need to create a username and password, and give that user permission to upload. You also need to create a directory large enough to hold the backups. You should test the FTP server by connecting from a desktop and uploading a file to the upload directory.

Next, you need to download the G4L ISO image and burn a CD of it. The G4L project page is http://sourceforge.net/projects/g4l. Once you have downloaded the image, you can burn it using a CD writing software package.

With the bootable G4L CD, you are ready to boot and back up a server. Insert the CD in a system and boot from it. The CD boots to a license and informational screen; once you press Enter to agree, you boot to a command line.

11.8.4. Using G4L

To start G4L, simply run the g4l command at the prompt:

bash-3.00# g4l

This displays the main menu. Here, you can choose Raw Mode or File Mode. The Raw Mode option is the one to use for most backups. File Mode requires you to set up a special server running partimaged. Don't worry, though; you can still do filesystem backups using ntfsclone in Raw Mode.

Raw Mode offers three choices: Network Use, Local Use, and Click' n' Clone. Choose the Network Use option. The Local Use option allows you to perform a raw backup or restore of a drive, or partition to a file on another drive. The Click' n' Clone option allows you to clone one disk to another.

Selecting the Network Use option displays a menu with 16 options. Don't panic; in most cases, you'll need only 3 to run a backup.

G4L defaults to using eth0 and DHCP to set network settings. These defaults are suitable for most environments, but if you need to change them, you can. The first option, A: Pick Device, allows us to select a different Ethernet adapter. Option B: Config Device allows you to set an IP address for that Ethernet device.

You must set options D: Config FTP, E: Config useridpass, and F: Config Filename before performing a backup or restore. D: Config FTP is the setting for the FTP server that you are backing up to. E: Config useridpass is the user ID and password for the FTP server. (You enter username:password.) F: Config Filename specifies the name for the backup.

Additionally, if the directory on the FTP server you are backing up to is not /img, set P: Path to Image Directory. You can also set the compression algorithm. G: Toggle Compression allows you to select None, GZip, Lzop, or BZip2 compression. Without getting into a battle royal over which compression method is best, lzop produces the fastest backups. Most users should use lzop because the backup will be smaller and run faster on most modern Pentium I or later machines.

With those settings, you can now choose how and what to back up. H: Backup allows you to select a drive or partition to back up. Once you select the partition or drive and click OK, the backup runs. Similarly, selecting I: Restore restores the raw backup from FTP. If you want to perform a filesystem backup, select N: NTFSCLONE Backup and then select from the available NTFS partitions. O: NTFSCLONE Restore allows you to restore an NTFS partition backup.

After making or restoring a backup you can see the summary performance data by selecting the T: Display Time option.

11.8.5. Customizing G4L

It is also possible to customize G4L for your environment. The easiest way to do this is to use a Linux development environment. You can set the menus to have different defaults by mounting the ISO image as a loopback device and editing the config files before you burn the CD. You can set the defaults in the G4L file itself by changing the variables netzip, server, useridpass, netimagename, device, and ftppath. The variables reflect in order the compression used, the FTP server IP address, the username and password for the FTP server, the default backup filename, the Ethernet device, and the FTP upload directory. You can also perform other customizations to the menus to remove choices that are not relevant to your environment.