# Backing up one external hard drive to another external hard drive?



## pacecom (Aug 27, 2016)

Hi,

I keep all my LightRoom files on a LaCie 4 terabyte external hard drive(HD1) so that I can plug it into either one of my 2 computers, where I have  LightRoom installed.

At the end of each days work, I copy (overwrite) the files to another external hard drive(HD2) attached to my main Mac computer, so I have an identical copy. (HD2) is backed up to the cloud, but it takes days for the new data to sync to the cloud.

Copying (overwriting) files was not much of an issue when I started out, but now it takes 6 hours to copy (overwrite) 660gigs of data.

Question: Is there a way to incrementally backup only the days changes of LightRoom to (HD2)? 

Is there software for the Mac that can do this? I only use Time Machine to backup my main hard drive.

Kind Regards,
Peter


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## Johan Elzenga (Aug 27, 2016)

Yes, there is a lot of software for the Mac that can do this. Here are just a few: Drive-cloning utilities: The best Mac apps for making a bootable backup. Because your backup doesn't need to be bootable, you have even more options. Just Google for it.


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## clee01l (Aug 27, 2016)

Welcome to the forum.   The simplest solution would be to use a dedicated backup app like Time Machine.  Or a third party backup app like CrashPlan.  
You have time machine on your computer, why  not use it.  CrashPlan is also free for local backups with an added plus that you can purchase a subscription fir unlimited cloud backup for ~$60USD. 
I use all three for the added assurance that I have two local backup copies in case a disk drive fails or I make a stupid users mistake.   The cloud backup is added insurance for some catastrophic event that might destroy my home with all of ,y computer equipment. 

Both TimeMachine and CrashPlan are background apps that run continuously making incremental backups of only the files that change  You all get version control so that you have recover a file that might have been changed or deleted days or months ago.


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## pacecom (Aug 28, 2016)

@JohanElzenga and @clee011, 

Thanks for your replies. 

SuperDuper, Carbon Copy Cloner, and CrashPlan all look like viable solutions to my situation.

I’ll research each product more thoroughly and decide which one to use. Looks like this forum is filled with experts.

I’ll be back if I have any more questions.

Thanks,
Peter


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## clee01l (Aug 28, 2016)

pacecom said:


> @JohanElzenga and @clee011,
> 
> Thanks for your replies.
> 
> ...


Don't leave out Time Machine
Time Machine is practically idiot proof. (It was designed specifically for Apple Mac users)


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## pacecom (Aug 28, 2016)

@clee01l 
I didn't think is was possible for Time Machine to backup my computer hard drive to one external (HD-TimeM), and backup my external hard drive (HD1-LR) to another external hard drive (HD2-LR) at the same time. There are 3 external hard drives involved in my case.

If I were backing up both my computer hard drive and my external hard drive (HD1-LR) to the same external hard drive, that would work. 

Am I mistaken?


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## clee01l (Aug 28, 2016)

pacecom said:


> @clee01l
> I didn't think is was possible for Time Machine to backup my computer hard drive to one external (HD-TimeM), and backup my external hard drive (HD1-LR) to another external hard drive (HD2-LR) at the same time. There are 3 external hard drives involved in my case.
> 
> If I were backing up both my computer hard drive and my external hard drive (HD1-LR) to the same external hard drive, that would work.
> ...


Yes, you are mistaken. 
My time Machine alternates backups to a Time Capsule (Network Drive) and a Locally attached Hard drive




You Manage what gets backed up by controlling what folders are excluded from backup.  By default, all External hard Drives are on the Exclude list If your critical user data resided on one of these excluded disks, simple edit the list to remove that disk.


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## pacecom (Aug 28, 2016)

This is very good information Cletus.

With this information, I’ll restate one more time what I want to do so you can advise.

I now have Time Machine backing up only my computer hard drive data to a My Book external hard drive attached to my iMac at all times. I don’t want this to change.

When I plugin my main LightRoom external hard drive (HD1-LR) I want that to start to incrementally back up to (HD2-LR), which is connected to my iMac at all times.

Whatever is backed up to (HD2-LR) gets backed up to the cloud via Backblaze.

You’re saying that this is possible?

Will Time Machine recognize when I plugin my LightRoom external hard drive (HD1-LR) and immediately begin to incrementally back up to (HD2-LR)?

Thanks Again for your help,
Peter


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## clee01l (Aug 28, 2016)

Sorry that's not the way Time Machine works.   You can Add the external hard drive (HD1-LR) to the Time Machine back up to backup everything including the external hard drive (HD1-LR) to My Book external hard drive.  Whenever the external hard drive (HD1-LR) is present Time Machine will backup any changes.

The other thing that you can do with TimeMachine is alternate backups between the My Book external hard drive and another designated Backup drive.  Time Machine runs only one backup process to one backup destination at a time though you can have more than one local backup destination.  TimeMachine app backs up everything mounted to your Mac except those file and volumes that you specifically exclude on the options panel.

If you want to back up the HD1-LR by using another backup app (like my favorite CrashPlan), you can have the additional backup app also running as a background task and dedicated to backing up only those files that change on HD1-LR.  I do have both TimeMachine and CrashPlan running in the background. I set up both apps though to back up the same files in different places.


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## pacecom (Aug 28, 2016)

That's what I thought. Thanks for validating. I'll look into CrashPlan.

Regards,
Peter


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## Jack Henry (Aug 29, 2016)

You need to look at ChronoSync. It will back up what you want to where you want.

You can set it to back up an external drive when it detects it mounting. So, if the drive is not plugged in all the time, the next time you connect it. ChronoSync will see it 'Mount' and back it however you've set it up. After the first 'full' backup, it does incrementals. AND you can include it to archive deletions to an _Archive folder on the backup drive. So if you delete something from the drive you are bcking up, that file will be moved from the backup set into an _Archive folder. You can also specify how many versions you want it to archive.

Version 4.7 (being released soon) will include cloud backup.


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## pacecom (Aug 29, 2016)

Thanks for the info Jack.
Already trying Carbon Copy Cloner and like it very much. I think it will suit my needs just fine.


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## Jack Henry (Aug 29, 2016)

Once backed up, can you just browse the cloned disk in Finder like a normal drive? Or do you actually have to run a 'restore' to get a file back?


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## pacecom (Aug 29, 2016)

Not sure Jack. Just testing the trial for now. Will look into ChronoSync too. I had it many years ago and it was so complicated that I gave up on using it. I really only have one single need, to backup up one external hard drive to another external hard drive. Carbon Copy Cloner is simple and works very fast. But thanks again for your input.


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## Jack Henry (Sep 2, 2016)

Just a bit more info about ChronoSync.


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## pacecom (Sep 2, 2016)

Thanks Jack!


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## Jack Henry (Sep 3, 2016)

Oh, one other little app that is really handy in relation to syncing drives and/or folders is VisualDiffer

You drag one folder (or drive) to one side of the app, another folder (or drive) to the other side of the app, and it displays what's different.

Once displayed, you can filter on various selections such as 'Only Mismatches', 'Only Matches', 'Orphans' etc

You can also copy from missing items one side of the app to the other


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