Question about size of back up disk

[Allen Webb]

I am a newbie using Retrospect on my home Mac. I created a duplicate of my laptop 111 gb hard drive (OS 10.4.11) on 186 gb TEAC portable hard drive.

 

To do this I first partitioned the back up hard drive into two parts, one of 111 gb (for the duplicate) and one of 74 gb, so that the part I was saving on would be the same size as my laptop hard drive.

 

This worked fine for several months. Now, however, Retrospect won't continue backing up because it says there is no more room on the duplicate hard drive. I do notice that there are some files on the duplicate that are old files that I believe are no longer on my laptop. I also notice that my laptop hard drive may be getting rather full (says I have used 100 gb and 10.8 gb are still available).

 

What should I do about this situation?? It scares me a little to wipe clean the duplicate hard drive, erase the partition, and start over -- though I guess that is a possibility. But then if I keep backing up in the same way, won't the same thing happen again eventually?

 

Thank you greatly for any help!!

[CallMeDave]

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I created a duplicate of my laptop 111 gb hard drive

 

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First of all, understand that in Retrospect parlance, "Backup" is very different from "Duplicate," even though the program is capable of performing both operations. While there are numerous OS X applications that do a good job at duplicating the contents of one volume onto another, including Apple's own Disk Utility, Retrospect's unique strengths lie in its Backup capabilities.

 

 

There are two different settings for Duplicate; "Replace Entire Disk" and "Replace Corresponding Files."

 

- What settings did you use?

 

- Have you read the Users' Guide section that talks about the difference between the two Duplicate settings?

 

Dave

[Allen Webb]

I used "Replace Corresponding Files." Does this information give some idea of what I should be doing differently or doing now?

[Allen Webb]

I think I understand the basic difference between "back up" and "duplicate." I believe I have (and want) a duplicate, where I can go back and forth between the disks, moving or saving files. Right?

[CallMeDave]

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Does this information give some idea of what I should be doing differently or doing now?

 

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Well, sure, _I_ have some ideas. But then, I've read (and re-read) the Users Guide on this subject.

 

If you want to keep a duplicate copy of your drive, without maintaining any record of lost or deleted files, you need to Replace Entire Disk each time. That will delete files off the Destination volume so that it always looks identical to the Source.

[rhwalker]

If your goal is to duplicate the entire disk, then Retrospect is not the right tool for that job. I would suggest SuperDuper!, although Mike Bombich has just released version 3 of Carbon Copy Cloner (CCC). Both are free.

 

If your goal is to do backups, so that you can go back to earlier states of your drive and files on the drive, then Retrospect is the right tool for the job.

 

Don't confuse backup with duplicate. They don't do the same thing, and don't serve the same purpose. Without knowing your needs and goals, it's not possible to advise which one to use.

 

You might want to review the following discussion of backup policy questions that need to be answered first:

What should a good backup policy address?

 

Russ