What is benefit of cloning rather than creating backup image?

[tuttle]

There are many posts here with questions and issues around cloning, and also people who clone when what they really should be doing is imaging. I have not cloned at all, only created disk images and done restores, so I'd like to ask:
What is benefit of cloning?
What does cloning offer that a backup image does not?

If moving to a larger drive, one can still use a backup image as an image can be restored to a larger drive and, IIRC, you can choose to use the larger space available on the new drive. So, when would you want to clone rather than image/restore?

[K0LO]

It saves a step:

Imaging: Source Disk > Image file > Target Disk
Cloning: Source Disk > Target Disk

Cloning cuts out the step in the middle but in the process you lose all of the advantages of creating images such as the ability to store multiple image files on a disk, the ability to selectively restore partitions or folders or files, etc.

[MudCrab]

I'll give you one example where I cloned instead of imaging and restoring.

I was replacing a RAID 0 setup and had reinstalled XP onto a single drive until the new RAID drives could be installed. After the drive installations, I decided to clone from the single drive to the RAID 0 array just to save time (that was the only reason). The clone went perfectly and the single drive is now the backup drive for the RAID 0.

[DwnNdrty]

Some people just like to have a "ready-to-go" drive. In fact a friend who runs a business keeps a cloned drive in a mobile tray which he can insert into his server at a moments notice if the server drive (also in a rack/tray device) quits on him. The cloned drive is updated every day. In fact I believe he actually alternates the drives daily.

[shieber]

It's a trade-off between saving disk space and having multiple backups (using image files) vs saving a little time (using a clone). Sort of like fail safe vs time safe.

[tuttle]

Thanks for the explanations. Given all that, it seems that the vast majority of folks who post with questions about cloning should really be making disk images instead.

[phil.brady]

-{ Quote: "Some people just like to have a "ready-to-go" drive. In fact a friend who runs a business keeps a cloned drive in a mobile tray which he can insert into his server at a moments notice if the server drive (also in a rack/tray device) quits on him. The cloned drive is updated every day. In fact I believe he actually alternates the drives daily." }-

I'm not sure I fully understand this.
If the source drive were to fail this would very likely show itself during a clone operation - he'd end up with a broken source and a part written destination, neither of which would be usable.
Doesn't his strategy need at least 3 drives?

Phil

[DwnNdrty]

-{ Quote: "I'm not sure I fully understand this.
If the source drive were to fail this would very likely show itself during a clone operation - he'd end up with a broken source and a part written destination, neither of which would be usable.
Doesn't his strategy need at least 3 drives?

Phil" }-
We're starting here with a known good clone so at the starting line we have two good identical drives. On day 1, say drive 1 is used and at the end of the day it is cloned to drive 2. On day 2 drive 2 is used and so on. If during any day the drive being used fails, it is swapped out. The only loss is what has been added that day, which can be recovered - in the case of this particular business with a little effort during some slack time. But at least the Server can be up and running in the time it takes to shutdown, remove bad drive, insert good one and boot up again - less than 5 minutes.

Of course the failed drive would have to be replaced to continue the cloning process.

[GroverH]

The sad part is that too many attempt a cloning procedure without any security net of current & complete backups. If things go wrong, they blame the software for something within their control.

[tuttle]

-{ Quote: "The sad part is that too many attempt a cloning procedure without any security net of current & complete backups. If things go wrong, they blame the software for something within their control." }- Precisely! From what I've read in these forums, most users would be far better off making backup disk images, not cloning.

[TheWeaz]

-{ Quote: "Precisely! From what I've read in these forums, most users would be far better off making backup disk images, not cloning." }-

Even when replacing a drive with an exact model/size drive, I always use images - never a clone.

[phil.brady]

-{ Quote: "We're starting here with a known good clone so at the starting line we have two good identical drives. On day 1, say drive 1 is used and at the end of the day it is cloned to drive 2. On day 2 drive 2 is used and so on. If during any day the drive being used fails, it is swapped out. The only loss is what has been added that day, which can be recovered - in the case of this particular business with a little effort during some slack time. But at least the Server can be up and running in the time it takes to shutdown, remove bad drive, insert good one and boot up again - less than 5 minutes.

Of course the failed drive would have to be replaced to continue the cloning process." }-

I still don't understand. You seem to be saying that he has only 2 drives and that he alternates them via a clone.

So.... let's assume that a bit of crud inside the drive moves or a bit of oxide falls off, or there is a power glitch which causes a head to scrape the oxide and a chunk of data becomes unreadable.
That bit of corrupt data may well not be accessed during business hours, but it will certainly be found during the clone. Alternatively the drive might just fail during the clone operation. At that stage the clone copy will be half way through and the previous day's clone will be un-usable. Result is two corrupt disks and lost service.

Phil

[MudCrab]

-{ Quote: "I still don't understand. You seem to be saying that he has only 2 drives and that he alternates them via a clone." }-
Cloning in this fashion should not be considered having a backup (in my opinion). As you say, the drive could fail and you'll be left with two corrupt drives.

Hopefully, there are "real" backups kept at hand that span a period of time so if something goes wrong it can be corrected easily with a restore or an older clone.

I think that most people who do this do it because of how quick it is to change drives if one fails. That's all well and good, but it almost puts you in the same boat as only having a RAID 1 setup. You still don't have any "backup" for a virus or corruption that happened prior to the last switch. In that case, both drives can already be messed up before you even find out about the problem.