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Using Clonezilla for simplified Linux server disk cloning

Using the open source tool Clonezilla can save Linux administrators time when performing the common task of cloning Linux machines. Learn how the tool works and what options and configurations are supported and available.

It's pretty much a given that every IT shop of any size uses disk cloning to roll out new desktops and often laptops to their employees. You take a newly received system, open up the box, pull out the hard drive and use either a hardware cloning device or a software-based method to copy an image from a corporate master complete with system configuration and software ready to go.

For the Linux admin there are a number of options at your disposal. Netcat is a reliable method for cloning systems over the network (see the recent tip on using Netcat). But, Netcat is a command-line solution and might be a little intimidating for the casual system administrator. Clonezilla is an alternative with a simple user interface that will appeal to both newbie and experienced admins.

Using Clonezilla
Clonezilla comes in two versions, Clonezilla live and Clonezilla SE (server edition). The server edition has the ability to clone in excess of 40 computers simultaneously. Clonezilla live is for single-machine backup and restore. It works using either a CD/DVD or a USB flash drive or hard drive. The idea is to boot from the Clonezilla live media and do all the disk cloning operations by answering a series of questions. Clonezilla SE requires a DRBL server for massive cloning operations.

Once you get the system booted you're presented with a series of menu screens allowing you to choose how you would like to proceed. The two basic operating modes of Clonezilla are device-to-image and device to device. For large scale image cloning you probably want to first make an image of the master disk and then use that image to create the clones. For individual disk cloning the single device-to-device option will be better.

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Choosing the device-to-image option requires you to answer an additional set of questions before you begin. You essentially have to specify where the image will be saved in the initial step and later where the image will be read from. Clonezilla supports a number of options including a local device, an SSH server, a SAMBA server or an NFS server.

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Once you have the device specified you must select the way you wish to save or restore the data on the hard drive. Options here include saving and restoring an entire disk or individual partitions.

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Clonezilla uses the open source tool Partclone to do the actual physical cloning of individual disk partitions. Partclone is a partition cloning tool with support for a multitude of disk formats including Ext2, Ext3 and Ext4, Reiserfs, Reiser4 and XFS on Linux, NTFS and FAT on Windows, HFS Plus on Mac OS X, UFS2 on BSD Linux and VMware's VMFS format used on their ESX servers.

For disk-to-disk cloning the process is even simpler. Once you select that option Clonezilla will prompt you for the source and then the target disk. It will ask you a few times if you're really sure before it launches off on its job. It's a good idea to know your hard drives by manufacturer and model number as that's how Clonezilla will present them to you.

Part of the process includes copying the boot sector of the target drive. In most cases you would want to copy the boot sector (Master Boot Record or MBR) because without it you won't be able to boot the disk. Some scenarios might dictate that you don't copy the MBR, so they provide this option. There's also a tool called DRBL-winroll. This is used for adjusting the Windows System Identifier (SID). It can also adjust things like the Windows hostname and workgroup name. This will come in really handy if you're using the tool to roll out Windows systems.

Performance could vary significantly depending on what devices you use for the storage of images. Disk-to-disk cloning should perform somewhere in the neighborhood of 50% of the rated performance of the drive. That would equate to around 1.5 GB per second for a typical SATA drive. I was able to get an average of 1.58 GB /second with a high-end AMD quad core processor.

Clonezilla is definitely a tool worth looking at to solve your disk cloning needs. It does rely on other open source tools to get the job done but integrates them into a single bootable image to streamline the process.

ABOUT THE AUTHOR: Paul Ferrill has a BS and MS in electrical engineering and has been writing about computers for over twenty years. He's had articles published in PC Magazine, PC Computing, InfoWorld, Computer World, Network World, Network Computing, Federal Computer Week, Information Week, and multiple Web sites.

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