Live filesystem “capture” into a virtual disk image

ah… the joys of *nix utilities…. I’ve just successfully tested a “capture” of a live, running system into a virtual disk image. No, I don’t mean that I booted up with an imaging utility. I took a live, booted and logged in system and imaged the primary hard drive that it was living on, into a file on another machine. (Yeah, I know, there are probably a few people reading this and saying they’ve done that and most people that would need to do this already know how…. sorry I missed the memo.) Not too long ago, VMWare released a tool to do something like this (that tool is for windows…) This should work on any platform that supports dd and netcat (although I’m not sure if piping output from one program to another works with a dos command shell – maybe cygwin would be a good environment to accomplish this with.) Anyway… here are the details.

I’m putting the finishing touches on a backup server and wanted to have vmware server installed and setup on it “just in case”, because with all the storage it could certainly host a virtualized mail server or something in a pinch. Well, my main concern was how to quickly and easily get an image file of a LIVE filesystem. I know I could boot up to ghost4linux or ghost4unix or something and image over a network, but that increases the downtime. Now, realistically if this were a live system you’d probably want to disable as many network services as possible first so that there wasn’t new information. This method will start at bit 0 of the drive and progress straight through. In other words, there’s no going back because something changed.

On the machine that will “receive” the image, here’s what you do…. sudo nc -l -p 9998 | dd of=testimage.img this starts netcat listening on port 9998 for data and anything it get’s will be written to testimage.img *(my first attempt at port 9999 gave the following:: Can’t grab with bind :: I suspect something else was already using port 9999.)

Ok, now on the system to be imaged… with netcat installed (and dd)… sudo dd if=/dev/hda | nc ipaddressofreceiversystem 9998 (in other words, we start up dd with the primary drive (drive to be imaged) as the input file and pipe it to netcat (telling netcat to connect to the address of our recipient system at the correct port (same as specified on the receiver.))

Now, for a 2GB test image this took, maybe 5 minutes, I didn’t time it, but it was not long. I found someone estimating about like this…. “Typically 36GB drive may take 50 minutes over 100Mbps link.” So, that might give you an idea of what kind of time to expect.

But, the file created here is not suitable for vmware to use… yet. If you have qemu-img (from the qemu emulator) you can convert it like this…. qemu-img convert testimage.img -O vmdk testimage.vmdk and then vmware can use it as an existing disk image. But if you don’t have qemu (it’s free/open source) you might download that, or try and see if vmware-vdiskmanager can convert to the vmdk from a raw image file. Scratch that, I’ve just found the vmware forums for accomplishing this and they look messy – get qemu and use qemu-img for this it will be much easier.

Related Posts

Blog Traffic Exchange Related Posts
  • Vmware launches beta of real to virtual converter Vmware has launched a tool (windows only it seems) aimed to convert a REAL running system into a virtual machine. (For use with VMWare's virtualization products. The converter also can convert images from competing virtual machine "platforms"(?) (Microsoft Virtual PC, Microsoft Virtual Server, Symantec Backup Exec System Recovery (formerly LiveState......
  • Running Google Earth under Wine on linux A while back I talked about Google Earth under Codeweavers wine almost working (or at least I think I mentioned it here, I KNOW I tried it...) Well, I tried with vanilla wine as well and couldn't get it to work, BUT... I've just finished a successful run of it.......
  • Apple Mac OS X Not Accepting Login So, there it is an Apple Mac configured to auto login is now showing a Login screen and it doesn't seem to like any of the usernames and passwords that we could think of. In other words we're locked out. I haven't done an awful lot of Mac support, but......
Blog Traffic Exchange Related Websites
  • Install Interior Window Shutters to Cool Your House If you’re dealing with a lot of windows in your home and you are worried about keeping it cool inside, one of the best solutions is interior shutters. They will cost more than drapes, but they are easier to clean and much more permanent. The look of interior shutters can......
  • Free Success Ebook: “The Law of Success – Lesson Three: Self-Confidence” by Napoleon Hill "You should be cautioned to learn the difference between Self-confidence, which is based upon sound knowledge of what you know and what you can do, and egotism, which is only based upon what you wish you knew or could do.  Learn the difference between these two terms or you......
  • How To: Programmatically Open Folders Recently as a part of support activity, I came across a unique task. This application had a windows service running on cluster of 8 different servers. To ensure that windows service is up and running, I had to check the timestamps of the log files this service was updating periodically.......
PDF24    Send article as PDF   

Similar Posts

See what happened this day in history from either BBC Wikipedia
Amazon Logo

Comments are closed.

Switch to our mobile site