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Kalkas
11-27-2009, 03:30 PM
Hello,

Curiously I compared size of two sparsebundle images of one and the same disk (main mac startup disk) which were located in the same partition, and they had different size. The difference between them was 7 GB; see the attached image which shows two sparsebundle images "current" and "testing." They are images of the same disk having the same content. "Testing" is a later image, made after "current," and there were no changes made on the original disk after "current" was made prior to creation of "testing."

Why is the difference in the size of these two images? Does it indicate that there is some error in the creation of one or both of these disks?

Kind regards,
Aleksandar

dnanian
11-27-2009, 03:32 PM
You can't really make judgements based on the external file size of a given image... did you look at the actual size of the volume when you open the image file?

Kalkas
11-27-2009, 07:36 PM
When images are opened, you get disks with different sizes, see attachment.

Kalkas
11-27-2009, 07:49 PM
However, I have compared home directory in each volume, and they appear to be same, with the same size and the same number of items, see attachment.

So, it seems that images are ok. I just wonder why is there difference in sizes of volumes?

Kind regards,
Alex

dnanian
11-27-2009, 10:59 PM
I don't know. I can only assume that there were significant differences on the source when these were made... but I just can't tell. There had to be *some* difference between these two copies.

Kalkas
11-28-2009, 07:10 PM
The only difference I see with these two images is that "current" was smart updated four times, while "testing" was created once, without any subsequent smart updates. Both images have the same source disk.

Kind regards,
Alex

dnanian
11-28-2009, 07:25 PM
I'm just not sure why they would be different. I'd have to suggest the source drives were different when they were both last smart updated...

Kalkas
11-29-2009, 03:46 PM
The reason for creating this thread is the peculiarity of the case. It is quite strange that one can get two images with significant different sizes although their last smart updates were from the one same source with the same content.

I have hoped that someone would give some idea why this this is the case.

Kind regards,
Alex

Kalkas
11-29-2009, 05:42 PM
I have made new comparisons of the images in question.

The overall size of the images, and their (mounted) volumes are different. However, when comparing the size of all folders at the root (with their number of items), I got equal numbers.

So, it seems that the backup images of the source are practically the same, even though they have significant difference in the overall size. I wonder why is there a difference, when practically all folders of the one volume have the same size with their counterparts of the other volume. There should, therefore, not be any difference in the overall size at all. Is this not quite a peculiar case?

Kind regards,
Aleksandar

dnanian
11-29-2009, 07:13 PM
It is peculiar, and I really don't know why it would be. I do understand why the images themselves would have different sizes, but not their contents.