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View Full Version : Bloated Backups! Smart Update resulting in an ever increasing sparse image?


Naismeth
03-02-2007, 10:41 AM
I perform a Smart Update every week to a sparse image file. Its now up to 400 gig though my drive thats being backed up is at 100 gig.

I thought Smart Update erased what was needed to keep the backup the same as the original.

I have no idea what is happening.

dnanian
03-02-2007, 11:27 AM
The external size of the image is entirely controlled by the way OSX itself manages the file. Internally, though, the size of the files therein should be correct. Is it?

Naismeth
03-02-2007, 02:15 PM
The external size of the file changes every time I do a backup. I think it increases everytime. The size of the files inside (shown once the image file is "mounted") is fine.

But this is terrible. If my image size is 430 gig and the files therein are only 125 gig I will run out of space when I don't need to.

It seems like the sparse image can increase, but is not reduced.

Is it possible that if there are 30 gigs of changes that are needed to be made to the sparse image during a SD Smart Update, the image file increases by that amount, instead of seeing there is plenty of room available in the image file?

I created this sparse image using the Apple Disk utility. I probably created it at 150 or 200 gig orginally. Is this the problem? I was under the impression that you had to do this because image creation within SD didn't work (OS flaw).

Should I create a read/write image file instead, then Superduper to it?
At least then if there was not enough space it would fail, not increase the disk image size.

dnanian
03-02-2007, 02:19 PM
If you'd like, you can create an image with a smaller maximum size. It won't grow beyond that...

Naismeth
03-02-2007, 02:27 PM
How do you specify a maximum size?

Sparse or read/write?

Should I create in Apple Disk Utility or select "image file" from the destination drop down in SuperDuper?

dnanian
03-02-2007, 02:34 PM
Sparse. The size you elect to make is the maximum size... use Disk Utility. In SD!, the maximum size will be set to the size of the source.

Naismeth
03-02-2007, 02:40 PM
Ok, I feel like I'm beating a dead horse here. Sorry for my lack of understanding . . .

This sparse file was originally create with Apple Disk Utility at a size of 200 gig or so. Based on your last response, this should be the "maximum" size and shouldn't exceed it. Yet is has, big time.

Also, I think that SD is copying files that it needs first. The OS sees that it needs to expand the sparse image to accomadate the files. Then SD removes files that are no longer on the original drive. But, meanwhile the spareimage has been increased and is not reduced.

I guess that is why I'm getting ever increasing image file sizes. But, again, these were created in Apple Disk Utility and would have had a size of 200 gig.

dnanian
03-02-2007, 02:42 PM
I can only suggest that the maximum size was not 200G when you created the image: I've never seen an image grow larger than its maximum size.

We do not copy first: we copy or delete as we encounter the files.

Naismeth
03-05-2007, 10:12 AM
Very tactfully said! :)

I'm going to delete the old image and start over with a smaller maximum size. Then watch it as things progress.

Thanks for a great program.

klmorin
03-06-2007, 10:59 AM
Is not the same problem which you answered benbean, 03-06-2006?

Smart Update image size increasing over time

That's the way sparse image work, benbean -- Apple doesn't seem to recover deleted space very well. You can recover it by typing the following in Terminal:

Code:
hdiutil compact

(there's a space after compact), then drag the image file from Finder into Terminal. Then, press Return. It'll shrink the sparse image as much as it can.

Hope that helps.
__________________
--Dave Nanian

dnanian
03-06-2007, 01:53 PM
No, not the same question, since this user is claiming their image is growing beyond its maximum size.

forty2
03-09-2007, 11:05 AM
So if I let SD make the sparse image, it will more or less reflect the actual used space on the source, but if I make the image w/Disk Util it won't? I have a sparse image of my boot drive that is 150+GB (it is a 160GB drive) but only about 70GB is used.

I will try the compact function, thanks.

dnanian
03-09-2007, 11:09 AM
SD! creates a sparse image with the "maximum size" of the original source volume. We create it with Disk Utility, so it's fine to create with Disk Utility if you'd like.