Ghost for Unix

junyoung writes "Hubert Feyrer released the latest version of g4u ("ghost for unix"), a NetBSD-based bootfloppy/CD-ROM image that allows one to easily clone PC harddisks by using FTP. Since it reads the disk bit by bit, it can create an image of any operating system and any file system. Besides, it's free (under BSD style license)."

hmms

[Anonymous Coward]

maybe this will work better than the dd way I've been using so far.. gotta give it a try

Alternatives

[Huff]

When i was reading the article i was thinking 'why do we need another bl**dy disk copier/ghoster/whateverer' But the link states that it can be used with all file systems, which is something i have yet to see in other utilities.

Good on the chap who wrote it.
I definantly will be using this in future.

Huff

Exellent!

[muixA]

The thing I dislike the most about Norton Ghost, is hat it's DOS based. Getting networking working, for SMB image transfer is not always easy...

Cloning PC-Unix boxes (Linux, etc), doesn't really require any special software though... When I need a new node for our EDA cluster, I boot tomsrbt, and run fdisk, and then kick off a script that pulls down an .tar.gz, and takes edits various /etc files to change hostname, IP, etc. Chroot, run lilo, and your done.
--
Matt

This is very nice

[K8Fan]

Ever since Symantec bought Ghost, they've been changing it from a simple, easy to use, small, beautiful and most of all SMALL utility to a typical bloated pile of junk. It's so nice to see someone develop an open and free version that recaptures the original idea - just copy the fricken hard disk already!

Only if it's the same size disk

[j3110]

If the target is 1 sector less, you aren't going to be able to use this tool. I still think tar and netpipes is the only way. (unless you use XFS, in such case the best way would be xfsdump, tar, and xfsrestore) I'm trying to write a multicast fileserver for just this purpose. I have a lab of hetrogeneous machines(I take what I can get from the university) that need to be clones(btw, don't forget to run lilo if you use tar/xfs, and don't forget to change the site-key for ssh). I'm ending up using a homebrew solution. There are other good ghost utilities out there that boot from a cdrom(BART perhaps isn't bad), but I still need my own custom solution because I'm not gonna be here forever to make this lab work, and it needs to be "put this in the floppy drive and select options from the menu" easy.

Huh?

[FreeLinux]

Ghost handles all file systems as well. They call it a sector by sector disk copy. In this case Ghost does not care what is on the disk, it copies the DISK rather than the filesystem or partition as it does by default. But as with g4u you can't resize and so forth with a sector by sector copy.

The only problem with Ghost is the licensing cost.

Re:g4u source code mirror

[DrZaius]

tar with the appropriate flags works much better. Also, if you run it on a system that doesn't write to the disk much (ie webservers) you can generally take a somewhat reliable backup without taking the system down to init 1.

Low level error correction

[yerricde]

isn't there a big chance that some bits would get corrupted?

Modern storage devices use error correction at a very low level. For instance, CD-ROM has three error-correcting codes: two in the CD layer [washington.edu] and one in the sector layer. In addition, a partition could be written to multiple discs in a manner similar to RAID 5, such that every fifth disc stored an xor of the four previous discs.

Re:Alternatives

[alsta]

As previously mentioned, copying bit-by-bit is something Ghost already does. The problem, and ultimately unfeasibility with this utility is that it DOESN'T recognize filesystems and structures.

That means that you can only restore an image to a disk in equal or larger size than that of the dump. It also means that if you have a larger disk you'll find that you'll end up with unused space or perhaps worse, a boot sector in the wrong place so that you can't even boot your system.

I do believe that this project has the ability to go further at some point, but right now, I see it as a NetBSD boot floppy with network drivers and a ramdisk which has dd(1).

Re:Ghost will not work...

[FreeLinux]

Wrong. Don't believe everything that M$ tells you. The only problem with ghosting the SID is that it breaks security since all subsequent images have the same SID, the OS still works fine. To resolve this security issue though, execute ghstwalker which locates and changes the SID to a new unique SID. Then all is well.

Re:Cold feet

[FreeLinux]

Try an OS upgrade on >2000 machines and then tell me this. Better yet, try an OS replacement, say Windows 95 to Linux on >50 machines and then tell me you don't see the point of cloning workstations.

Re:Cold feet

[wfmcwalter]

I'd be interested to see if anyone can justify this, I just don't feel overall comfortable with the concept of UNIX cloning.

Okay, here's a few, and there's many more from whence these came:

1. You're the lab manager for a large university. You just bought seven hundred identical PCs. You have one week to install a customised kernel, a variety of applications, and lots of site-specific settings onto each machine.
2. You're the above lab manager and several hundred of those machines will sit in a public lab with no grown-up to police them. Experience tells you that student pranksters will do stuff to these machines on a pretty regular basis. Each student is supposed to keep all their work (on an ongoing basis) purely on their network-mounted directory. So you want to periodically (ideally nightly) have the machines return to a known software state.
3. You're the lab manager for the QA department of a large software company. A lot of the tests that the testers perform involve installing new software, performing the necessary patches - these must be performed on machines with exactly the correct software setup, otherwise the test is invalid. Generally, running each test takes less than an hour. You don't want testers sitting waiting for their (rare) test machines to reinstall any longer than absolutely necessary.
4. You're the production manager for a large PC company. You make production runs of thousands of identical machines each day. Time is short, and the production engineers won't let you specialise a given harddrive on the line until its actually inserted into a machine (very common), so you want to very quickly have production machines netboot and pull down their software image. Every minute a machine spends on the production line cost the company a dollar.

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[account_deleted]

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Re:Does anyone have first hand experience?

[Anonymous Coward]

The fact that you don't consider reading raw data from a partition to be a practical purpose shows you've never worked in IT.

This type of program isn't marketed towards the standard computer consumer, it's marketed towards server operators and up.

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[account_deleted]

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Re:I fail to see anything new here?

[hubertf]

Of course there is nothing new in g4u, it's just Unix after all.

But why spend an afternoon surfing the web for alternatives to Ghost, DriveImage and friends when you can rewrite your own version from which you know what it does, and while there get famous on /.?

- Hubert

P.S.: Does Ghost etc. support Gigabit Ethernet? USB Ethernet? Token Ring? No? Of course not - have fun finding the necessary DOS drivers.
See the g4u webpage for reasons why I wrote this. :)