Computer cloning, also referred to as ghosting or imaging, involves setting up the operating system, drivers, software, and data on one computer, then automatically replicating the same setup on other computers. Clonezilla Server Edition and FOG are the most popular open source cloning systems. While both do similar jobs – clone and restore machines over the network using tools and services such as partimage, tftp, and PXE – they go about it very differently. Which is right for you depends on your network's configuration and composition.
The most visible difference between the two solutions is in their user interfaces. Clonezilla has an archaic ncurses-based interface, while FOG provides a web-based interface that you can access from any computer on the network. It also has a special UI that lets you deploy images from mobile devices.
While both FOG and Clonezilla SE can handle multiple images, FOG is better designed to manage multiple images. With FOG you can logically arrange images in groups, such as Accounts Department or Labs or Lounge. FOG also scales better; it features a storage manager that can control a group of NFS servers that all host images. Multiple servers can serve images, taking some of the stress off the main FOG server and speeding up cloning, especially in large networks.
In an enterprise where you have a large number of computers to deploy, the best course is to deploy images across the network, which requires setting up a dedicated cloning server. For Clonezilla SE, this means setting up a Diskless Remote Boot in Linux (DRBL) server by installing it on top of a Debian or CentOS server. If you manage a small network and don't want to earmark a computer as a permanent DRBL server, you can use the DRBL live CD to convert any machine into a server temporarily to broadcast images created by Clonezilla and stored on a local disk to any computer on the network.
To use a cloning solution effectively, it's best if computers on your network have similar hardware components. If your network is made up of computers with different components, you'd need to manage lots of different images.
As for FOG, its installation script creates the components required for an imaging server on top of a standard LAMP server. Unlike Clonezilla's DRBL server, the FOG server is designed to integrate with existing network infrastructure such as DHCP and DNS servers, although it can also set these up on its own. Setting up a FOG cloning server is pretty straightforward, but if you're using an existing DHCP server you must tweak it to forward PXE traffic to the FOG server, and configure the firewall to pass traffic to the server.
If all of the machines you want to image are not on your network, you need a solution that can clone offline machines as well. To do that, you create a master image, copy it on to a removable USB disk, and deploy from that. Clonezilla lets you save an image to a disk and then clone it either over the network or by physically going over to the computer. FOG doesn't – you can clone only from an imaging server.
After an image has been deployed, both Clonezilla SE (with DRBL-Winroll) and FOG (with its client service) can integrate the cloned machines into an Active Directory domain.
Other cloning options Clonezilla SE and FOG are designed for cloning and deploying multiple computers over a network, but they both require setting up a dedicated server. This is overkill for situations where you just need to quickly image a disk, as you would for example when switching to a bigger hard drive. In such a situation, you might consider using one of these open source disk cloning applications:
While that's just about the extent of Clonezilla's capabilities, the FOG service can do a lot more. It can schedule tasks, such as deploying images, from its web interface, and perform several tasks other than imaging, such as installing and managing printers, tracking access to cloned machines, powering up a computer remotely using Wake-On-LAN, and installing applications remotely via a feature called snap-ins.
With snap-ins you can directly push the executable installer for a simple application to a Windows computer. For a larger application such as Microsoft Office that requires multiple files for installation, you need to use a tool like SFX Maker instead. FOG snap-ins don't have to be associated with an imaging task, so they can be used for things such as pushing software updates to client computers.
If you don't need to keep track of machines after cloning them, as might be the case, for example, in a repair or service center, Clonezilla gives you an edge over FOG. With Clonezilla you don't need to register a host with the server before it can be cloned. In contrast, FOG, by default, not only requires hosts to be registered before they are imaged, it also needs to register clients before it deploys images to them – though by using the Capone plugin you can override FOG's default behavior and clone a computer without first registering it with the server. Registering hosts has advantages, however, especially on enterprise networks. While registering hosts, FOG records the unique MAC address of their network cards, which reduces the chance of mistakenly deploying an image to the wrong machine.
While FOG is a fine enterprise imaging solution, it also has many of the features you'd want from a network management app. For example, in addition to options for registering and deploying an image, FOG's menu offers options to wipe a disk, restore deleted files, scan a disk for bad blocks, and run a virus scan using ClamAV.
If you're choosing between Clonezilla and FOG and you have machines that aren't connected to a network, you have no option but to use Clonezilla. You have to take an image with you and deploy it on each machine, but that's still faster than preparing each disk and installing and setting up an operating system on each individual client.
Clonezilla SE makes the most sense for networks with clients that don't require much administration after being imaged, such as those in Internet cafes, libraries, and school labs. If you need to look after machines after they've been cloned, it's best to go with FOG. Its post image options are excellent, and you can deploy machines without leaving your own desk.
The bottom line is that, while Clonezilla works best for offline computers and individuals, FOG has all the features you need to manage and deploy images in an enterprise.
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