Backup Strategy?
 

I have a new 320 GB iMac, and added two 750 GB external drives. Currently, I’m using both externals for Time Machine backups. I now want to use SuperDuper! to also create a clone backup(s).

My original thought was to continue to use one of the externals for a Time Machine backup, and delete the TM backup on the second external and use it as a SuperDuper! clone drive. Given that the externals are more than twice the size of my internal drive, that seems like I’ll end up with a SuperDuper! drive with a lot of “wasted” space.

Does it make sense to erase and reformat the second external into two partitions—a 320 GB volume for the clone and a 430 GB volume to “archive” files I no longer “need” on my internal (but which I don’t want to permanently delete)? My objective, of course, is to achieve the "best" backup "insurance" while making most efficient use of available drive space.

Yes, that makes complete sense. Remember, of course -- if you don't back up your archive it's also vulnerable, right?

Would that be preferred to using the second (430 GB) partition for a "slimmed down" TM backup (slimmed down compared to the TM backup on the other, 750 GB external)?

1. Yes...until (of course) I begin to run out of space on my internal drive, and need to (finally) delete those "archival" files from the internal, and maintain a (single) copy on the external.

2. What is the best way to use SuperDuper! for both the clone backup as well as the "archival" backup?

Is it preferred? Yes -- because Time Machine does not guarantee that your 'archived material' will be preserved, at all. Once it runs out of space for backups, it starts deleting older backups. It is not an archive.

To back up both your main drive and archive with SD, you'd need two destinations. I'd have a separate drive for the archive: I never store a backup on the same physical medium as the source.

So, the procedure is

1. Use one of the externals for TM;
2. Partition the other into a 320 GB volume and a 430 GB volume;
3. Use SD to create the clone on the 320 GB volume, beginning with an initial "Erase, then copy," and followed subsequently with "Smart Updates"; and
4. Use the 430 GB volume to "archive" selected files.

What's the best way to use SD to accomplish #4?

You wouldn't use SD! to do that: you'd drag the files you were going to erase to that partition.

OK.

One final question (sorry for being such a PITA ;) ):

I could (if I wanted to) partition the SD external into 3 partitions: 320 for the clone, and, say, 215 for the "archives" and the remaining 215 for a very "skinny" additional (to the 750 GB TM external) TM backup (until such time as I might decide I need that last 215 for additional archives), correct?

I don't understand how you could add to your TM backup; that's not how TM works.

I'm currently using both 750 GB externals for TM backups...I simply alternate them each day. So, if I keep one as the "main" TM backup, can't I then use a 215 GB "portion" of the other as a smaller TM volume (while using the remaining 320 and 215 volumes for SD! and "archives," respectively)?

I guess I just don't understand why you'd do that: it's really not of sufficient size to support a reasonable TM series.

The purpose is strictly to have a last-resort TM backup, in case the TM drive fails.

In the past, I've had some drive failures that have made me "paranoid" about having sufficient backups. Perhaps, to have the maximum confidence, I should've gotten a couple of TB externals, each with SD! clones, TM backups, and "archives." But I didn't, and was simply looking at this scenario as a potential "band aid" for my hard-drive-failure paranoia.

I think your SD! backup is that, though; having to switch back and forth with Time Machine is going to make your backups less effective, given the fact that the 2nd one is so small.

If I create only two partitions, and one is a 320 GB volume for my SD! clone, then the other will be 430 GB for any document "archives." Reserving 430 GB of archive space for a 320 GB internal drive will end up wasting a lot of space, since I can't imagine needing archival space that's 134% the size of my entire internal drive.

I thought that a three-partition approach might enable me to at least save some "history" of "older" documents, in case the main TM drive dies.

You're welcome to do whatever you want, Nick, of course! :)

Dave, I apologize if it appears I'm giving you a hard time :( ...honestly, I'm simply trying to understand which alternatives make the most sense, and I very much want to gain from your expertise and experience :) .

What else might I do with the 430 GB of extra space on the SD! external?