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jbleisure · Jan 6, 2006, 11:56 AM

Hi,

After an application crash a few months ago ( entourage!) I wisely invested in an external firewire drive and a copy of superdouper to clone my system to the external. (and am very pleasd with both).

However in my reserch for this I saw several people say that aclone is not a backup.

Is this the case?

What if the external is kept in a different location to my PB? Surely that is what a backup is.

Any thoughts?

rickey939 · Jan 6, 2006, 12:00 PM

I consider it a backup.

Tesseract · Jan 6, 2006, 12:15 PM

I consider it a form of backup.

It's not the best kind of backup, though, since (a) it may use more space than a 'traditional' backup, and (b) restoration from a disk image is typically all-or-nothing: you may not be able to do a partial restore.

SMacTech · Jan 6, 2006, 12:26 PM

Kind of silly that someone would not consider a clone of something a COPY of it. Backups come in many forms, a cloned drive would be one.

OreoCookie · Jan 6, 2006, 01:09 PM

Cloning a drive is not a sensible backup strategy for several reasons. First of all, it's a waste of space, if you clone 200 GB of data, it will take 200 GB of space. Do it again, and you need 400 GB.

Incremental or differential backups on the other hand will only 1) copy the data that actually needs backup and 2) later on only copy the changes. Also, depending on what kind of cloning you may refer to, if a drive is cloned bit-for-bit, then things are even worse, because you also copy possible errors in the directory and file structure onto the backup. Since cloning utilities usually clone the whole drive, you also clone problems of your old installation onto your recovered system.

Obviously having several versions of your data is essential, because if you were to keep only one, you would not be protected against accidental deletion for instance.

Just one word of caution here: a very popular software, Carbon Copy Cloner, is – despite its name – nothing but a front-end of various backup tools such as ditto and psync (a relative of rsync). However, it suggests to the user that there is an advantage of having a bootable clone of your drive when there is really none in most cases.

In a nutshell, keeping just a (bootable) copy of your drive gives you a similar security of a RAID1, it does not satisfy the necessity of having several different versions of your data to protect against corrupted files and accidental deletion.

An OS X installation does not take long compared to copying data (at least in my case, I have close to 60 GB of data on my PowerBook), so copying the files usually takes longer than an OS X installation.

Person Man · Jan 6, 2006, 01:27 PM

Originally Posted by OreoCookie

Cloning a drive is not a sensible backup strategy for several reasons.

Depends on your needs, and the level of risk you're willing to accept.

OreoCookie · Jan 6, 2006, 01:39 PM

Originally Posted by Person Man

Depends on your needs, and the level of risk you're willing to accept.

Nope, it doesn't. I can only think of various applications of cloning drives, but none of them are related to backing up data. A cloned drive has pretty much the same effect as a RAID1.

Real backups are faster and offer to store more than one version of your data. If you clone your drive each time, it would take hours – time which is literally wasted.

(Also note: I said, cloning is not a sensible backup strategy and not that it isn't a form of backup.)

jmiddel · Jan 6, 2006, 04:13 PM

OreoCookie, I have a question: I usually backup using SynchronizePlus!, but every now and then I erase one of my backup drives and clone the original to it, with the idea that I am creating a fresh copy, whereas in the backups I worry that some corruption will eventually creep in. Using CCC (and the erase) the cloned copy stays the same size as the original so I don't lose space. Is this procedure not necessary and am I just being a tad paranoid?

Many thanks for your knowledge, expertise and willingness to share!

OreoCookie · Jan 6, 2006, 04:34 PM

Originally Posted by jmiddel

OreoCookie, I have a question: I usually backup using SynchronizePlus!, but every now and then I erase one of my backup drives and clone the original to it, with the idea that I am creating a fresh copy, whereas in the backups I worry that some corruption will eventually creep in. Using CCC (and the erase) the cloned copy stays the same size as the original so I don't lose space. Is this procedure not necessary and am I just being a tad paranoid?

Many thanks for your knowledge, expertise and willingness to share!

Doing it your way is less secure than otherwise. You lose space in the sense that if you want to clone your data twice you need twice the size of your drive capacity.

With incremental backups, you just need (roughly) the amount of data which has changed. So the backup program just has to check which files have changed and then add those. Then you can restore each point in time, especially the backup before the corruption took place.

romeosc · Jan 7, 2006, 02:01 PM

I do both.... Clone for emergency us (40 GB firewire drive) in case of catastophic failure or loss of PB on road! Saved my bacon more than once! Just make sure to keep clone in a separate safe location! I even keep a Thumb drive with essential files in PDF format so I can use on another computer in case of theft! Make sure to make files usable by PCs since most hotels don't have Macs!

I also do weekly sequential backups!

romeosc · Jan 7, 2006, 02:03 PM

I do both.... Clone for emergency us (40 GB firewire drive) in case of catastophic failure or loss of PB on road! Saved my bacon more than once! Just make sure to keep clone in a separate safe location! I even keep a Thumb drive with essential files in PDF format so I can use on another computer in case of theft! Make sure to make files usable by PCs since most hotels don't have Macs!

I also do weekly sequential backups!

new newton · Jan 7, 2006, 02:20 PM

Originally Posted by OreoCookie

However, it suggests to the user that there is an advantage of having a bootable clone of your drive when there is really none in most cases.

Unless, of course, your time matters to you. Having had a drive die and just switching to the clone that was made the night before seemed both advantageous and sensible to me. Given some of the things I've seen you say, I can see how you might think this was a waste of space and inefficient. We appear to live in quite different worlds.

A cloned drive has pretty much the same effect as a RAID1.

That's a stupid thing to say. A clone is incremental in nature. If I hose a file, I can grab a copy from my clone. If I hose a file on a mirror, the mirror drive will--of course--just have the hosed file on it.

I'm not at all sure why you offer up your two cents on topics such as this. Your comments are worthless.

tavilach · Jan 7, 2006, 03:44 PM

Oreo, what do you think of SuperDuper's incremental backup? The space required to backup 200GB is 200GB, but from then on the backups are incremental and fast. Of course, one could always change the script to backup just what they want.

Detrius · Jan 7, 2006, 05:03 PM

Originally Posted by romeosc

I do both.... Clone for emergency us (40 GB firewire drive) in case of catastophic failure or loss of PB on road! Saved my bacon more than once! Just make sure to keep clone in a separate safe location! I even keep a Thumb drive with essential files in PDF format so I can use on another computer in case of theft! Make sure to make files usable by PCs since most hotels don't have Macs!

I also do weekly sequential backups!

Doing both is a better backup strategy than just using a single clone. Using just a single clone is a backup strategy, but far from optimal--after all, what happens if your hard drive gives up the ghost in the middle of updating your clone? Did you just hose your only backup? What if the clone actually hosed the one backup, but you didn't notice, and then your main hard drive dies?

You guys shouldn't be taking this as a personal attack. It's like saying that waiting until the light comes on in your car to refill your gas tank is not an optimal gas refilling strategy. It's better than waiting until you run out of gas, but there are issues that come with the method.

OreoCookie · Jan 7, 2006, 07:45 PM

Originally Posted by new newton

Unless, of course, your time matters to you. Having had a drive die and just switching to the clone that was made the night before seemed both advantageous and sensible to me. Given some of the things I've seen you say, I can see how you might think this was a waste of space and inefficient. We appear to live in quite different worlds.

We don't live in different worlds. I've had three drive failures last year and all I really lost were three not so important files, so I think my backup strategy is actually working

Anyway, my main machine is actually a PowerBook and swapping drives on mobile Macs is an entirely different story.

Originally Posted by new newton

That's a stupid thing to say. A clone is incremental in nature. If I hose a file, I can grab a copy from my clone. If I hose a file on a mirror, the mirror drive will--of course--just have the hosed file on it.

Unfortunately, an incremental backup is something else than what you have in mind. An incremental backup will compare the data which is to be backuped with your last backup. It will then only write the differences between the two. This means, every time you run your backup software, the differences compared to the last backup will be written on the backup medium (be it a tape, a harddrive or whatnot).

A somewhat related method is a differential backup; there all changes between the last full backup and your current state are written in one backup so that restoring your data will be quicker, but you need more space.

In both cases, essentially the same thing is accomplished, you can go back to an arbitrary backup without the need to write all your data onto a disk. So if you clone your drive, all you have is one measly copy of your data. You backup again before realizing something is wrong and you're screwed. Also, as Detrius points out, if you screw up during the cloning process, your backup is history.

Originally Posted by new newton

I'm not at all sure why you offer up your two cents on topics such as this. Your comments are worthless.

This is uncalled for.

OreoCookie · Jan 7, 2006, 08:02 PM

Originally Posted by tavilach

Oreo, what do you think of SuperDuper's incremental backup? The space required to backup 200GB is 200GB, but from then on the backups are incremental and fast. Of course, one could always change the script to backup just what they want.

It does exactly what people advertise here: you can make `snapshots' of your system at different times without the need of writing all data every time you backup.

Just give it a try, it seems easy enough

(Personally I (have to) use Tivoli Storage Manager, because my university offers a backup service, so I haven't used SuperDuper yet. But the principle is the same.)

kcmac · Jan 7, 2006, 10:59 PM

It seems like a lot of the posts are saying the same thing but differing on semantics.

I use SuperDuper. It starts off by making a bootable clone. The next backups after that work off that clone and only add to or remove the files that have changed since the last backup.

Whether you call this a clone or an incremental backup, in the end you still have a clone.

What I wish SuperDuper had was an archive feature of some sort that would save the files that are removed from the clone/incremental backup and put them into a separate file for future reference or use.

chris v · Jan 7, 2006, 11:24 PM

Same here. I initially cloned my entire drive (I always do this just PRIOR to OS updates), and have set Deja Vu to write incremental backups of whatever has changed from my main drive to the cloned one weekly.

I had a near-catastrophe about 6 weeks ago when my wife's iPod hard drive died, and tried to take my G5 with it. (don't ask me how, but I had a very corrupted drive in the G5 the same day the iPod drive crashed) I booted from the clone, and ran disk warrior, and when it showed several overlapped files, some of which weren't recoverable, I simply nuked and paved, then cloned it back. I was done recovering in an hour, and all I lost was 2 days worth of junk mail, and an install of the Sims.

ghporter · Jan 7, 2006, 11:25 PM

ANY backup is better than no backup. But there are smart ways to do it that are more economical and selective than multiple cloned images. A clone is just a snapshot-and a good basis for a full restore backup-but most systems only have changes in a few files most of the time; a clone would capture that and all the files that were not changed too, wasting lots of time and storage.

kcmac · Jan 8, 2006, 11:49 PM

Just to be clear, SuperDuper is not making another cloned image. It is modifying the original clone, taking out the files that are gone and adding the ones that are new. Only one clone or backup is being used. There is no waste of time or storage.

My incremental backups usually take about 5 minutes or less.

jmiddel · Jan 9, 2006, 12:12 AM

Hi all, this discussion has been very illuminating and helpful. Most people here mention SuperDuper. I use Synchronize! X Plus for the same purpose. Does anyone have a reason to prefer SD to Sync+? Thanks!

jbleisure · Jan 9, 2006, 08:12 PM

Thanks, All has been helpful....I can see the issue of backing up more clearly now - very helpful

Since EBCDIC · Jan 11, 2006, 10:20 PM

I've used both SuperDuper and Synchronize Plus in the recent past, and although I use the former currently they're both fine apps which do what they claim.

Your clone (which is a backup) is a good first step. Having a mirror in case of stupidity (I tossed what!?) or hardware error is great. But it doesn't help you in case of catastrophe (a fire in the house whilst your PowerBook is sitting next to the mirror drive).

What I'm doing is using Dantz Retrospect to backup *the mirror*. I chatted with a Dantz person about this at Macworld today, so I fell comfortable sharing this. Retrospect is hampered by the speed of the DVD burner, and for a big backup one finds oneself with the bad choice of either not touching the machine while the backup is happening or changing some files (and wondering whether the subsequent verification errors are because of bad media or casual use).

Backing up the clone mirror does away with this drama. Retrospect can take its time burning as many DVDs as it needs, and I can use the machine (changing files on the main hard drive) without worry.

You must then TAKE THE BACKUPS OFFSITE, like a shoebox in your mother-in-law's house or a bank safe-deposit box. You can even take a retrospect installer CD and one set of backups along on a business trip, should a few files go missing or a catastrophe take your whole drive. After laying on a new OS you can restore all or some of what was affected.

Good luck with getting a backup strategy that covers both bases.