Please advise on the best backup

[xslord]

Hi i am new to SD (as i am evaluating it) at this moment it looks very promising!

Below is what i am using for the evaluation:


MacBook Pro 15" Unibody (APR'09):
With 2 partitions, one for the OS (Snow Leopard) and one for DATA


Freecom USB 2.5" 250GB External Harddrive
With 3 partitions, one with a copy of the SL Installer DVD, one OSX (10.5.8) Boot partition (with SuperDuper installed), and one for Data.


Question:
Can i create a backup (read only image) of Snow Leopard boot up partition on the MacBook Pro, when i bootup from my external USB HD.

Or should i boot from my MacBook (SL), install and run SuperDuper from there and do the backup?

Thanx for your advise

[dnanian]

You should not copy Snow Leopard from Leopard, no. And I would suggest a read/write image, not a read-only one (which is slow and can fail during conversion if any I/O errors or disk space issues occur).

[xslord]

You should not copy Snow Leopard from Leopard, no. And I would suggest a read/write image, not a read-only one (which is slow and can fail during conversion if any I/O errors or disk space issues occur).

So if i understood it correctly i should create a backup of SL by booting and runing SD from another OSX startup (like from an external boot drive or another boot partition)?

[dnanian]

No, it's fine to copy the drive you're running from... but if you want to start up from an external HD, you should be running Snow Leopard to copy Snow Leopard.

[xslord]

Hi dnanian

Thanx for your reply, could you be so kind and explain why it is better to create an SL image from an external startup which is also SL?

Cheers

[dnanian]

You're going to get a more accurate copy if the drive isn't in use, since its files won't/can't change. However, in the vast majority of cases, those changes have no real effect.

[xslord]

Thanx again for your reply Dave,

But what i meant was : does it make any difference if i boot from an external drive (USB HHD with Leopard 10.5.8) and then make an image/backup of my MacBook (Snow Leopard)?

[dnanian]

Yes. I can only say that so many times. Do not copy Snow Leopard from Leopard.

[xslord]

Once again thanx for replying, but please forgive me if i asked it once more:

Why can't one not make an image from Snow Leopard by running SD from a Leopard Startup, please explain.

I know you mentioned this on a previous reply:
You should not copy Snow Leopard from Leopard, no....

But i really would like to get some more (technical) details, to understand the reason (and to be able to explain it to others)

Thanx for your effort!

[dnanian]

Because there are new features in the new OS, including compressed files, that aren't supported fully by earlier versions.