Backup Strategy?

[Nick]

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.

[dnanian]

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

[Nick]

Originally Posted by dnanian

Yes, that makes complete sense.

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)?

Originally Posted by dnanian

Remember, of course -- if you don't back up your archive it's also vulnerable, right?

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?

[dnanian]

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.

[Nick]

Originally Posted by dnanian

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?

[dnanian]

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