unix command for mounting a sparse image

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Level 1

26 points

unix command for mounting a sparse image

Hi,

I'm running a back up program (SuperDuper) and have my backup files all bundled up in a sparse image file on a remote disk connected to an airport extreme. In the Finder, if I double click on the backup.sparseimage file (which is over 80GB in size) then it proceeds to check the image's checksum (over the slow 80211g airport) and puts up a dialog box with a barbershop progress meter. The checksum checking operation can be aborted by clicking on the Skip button and the image mounts right away. If you don't skip the checking, it takes over an hour just to mount!! I need to be able to mount this sparse image under program control. Is there a unix command that can mount the image and bypass the checksum checking that the Finder insists on doing? All I'm trying to do is find a solution to this problem so I can pass it along to the developer.

Thanks in advance for your response(s).

Mick.

17" MacBook Pro C2D, Mac OS X (10.5)

Posted on Mar 17, 2008 7:21 AM

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Answer 1

Zerwas

Level 4

1,154 points

Mar 17, 2008 7:40 AM in response to Mick Mueck1

Try:

hdid image.dmg

or

hdiutil mount -noverify image.dmg

or open the DiskUtility. Choose Preferences>Mounting and deactivate the checkbox Verify Checksums

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Answer 2

Mar 17, 2008 7:47 AM in response to Mick Mueck1

Hi Mick,

Give this a try:
hdiutil mount -noverify your.sparseimage

--
Cole

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Answer 3

Mick Mueck1 Author

Level 1

26 points

Mar 17, 2008 8:25 AM in response to Zerwas

Thanks for your replies Zerwas & Cole.

I tried:

hdiutil mount -noverify image.dmg

and I believe it did do the verify operation. It took a little over 10 minutes, which is about the same as the Finder when I let it do the mount without skipping the checksumming. In case you're wondering why that time is so much shorter than previously quoted, it's because I did it on a current laptop running the much faster 802.11n. On the other much slower machine running 802.11g it's over 1.75 hours (I gave up after waiting that long).

I can't use the Disk Utility method because that's not possible under program control (I believe). Disk Utility does not support AppleScript.

I also tried the hdid command and it took about the same time to mount so I'm assuming it also did a verify.

So then, non of these commands worked as fast as the Finder when I click on the Skip button 😟.

Anymore thoughts?

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Answer 4

Mick Mueck1 Author

Level 1

26 points

Mar 17, 2008 9:27 AM in response to Mick Mueck1

Hooray - you guys pointed me in the right direction. I checked out the man page for hdiutil and it turns out that that by default fsck is done on all previously unmounted volumes. So this is the command I needed:

hdiutil attach -noverify -noautofsck myfile.sparseimage

Thanks again for your help.

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Answer 5

Zerwas

Level 4

1,154 points

Mar 17, 2008 9:42 AM in response to Mick Mueck1

Nice, that it still works.

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