1TB Disk Image ok? and backing up?

sparkie7

macrumors 68020
Original poster
Oct 17, 2008
2,037
106
I have ordered a 1TB G-Drive Mini to back up all my photography files. As this drive will be mobile or left in a different location to home and work I would like to protect it. So thinking a password protected Disk Image might be the way to go.

As far as I know, Apple does not offer any software to protect an external drive or volume. ie. like a Password to open and mount the drive. So is an encrypted Disk Image the way to go? And is 1TB ok, or is it too large?

At the moment I have a 1TB partition on a 3TB Hitachi internal drive in my Mac Pro where I store all my photography files. But wondering now that when I want to clone it using CCC to this 1TB Disk image will it still work ok? ie. my source drive/partition is not a Disk Image. Do I need to back this up. Wipe it and create a 1TB Disk Image (or say 990MB Disk Image as 1TB is too big as it needs other system files also) and THEN clone this to my G-Drive Mini.

Or can I leave the Source partition alone. Then create a Disk image on the G-Drive. Then when I want to clone it, mount it. Then open CCC to clone to the Disk image. Hope this make sense. Which option is better?

Any advice, suggestions on how to set this up appreciated.
 

Dark Dragoon

macrumors 6502a
Jul 28, 2006
843
3
UK
As far as I know, Apple does not offer any software to protect an external drive or volume. ie. like a Password to open and mount the drive. So is an encrypted Disk Image the way to go? And is 1TB ok, or is it too large?
Apple supports full disk encryption on Lion and newer (works the same way as FileVault2) so you can just encrypt the whole disk. In Disk Utility you partition the disk and choose "Mac OS Extended (Journaled, Encrypted)". Then whenever you plug the disk in it will require a password to unlock (you can save this on your computer so it's unlocked automatically if you want).

This should be a better alternative to encrypted disk images, unless you need it to work with computers running Snow Leopard or older.

At the moment I have a 1TB partition on a 3TB Hitachi internal drive in my Mac Pro where I store all my photography files. But wondering now that when I want to clone it using CCC to this 1TB Disk image will it still work ok? ie. my source drive/partition is not a Disk Image. Do I need to back this up. Wipe it and create a 1TB Disk Image (or say 990MB Disk Image as 1TB is too big as it needs other system files also) and THEN clone this to my G-Drive Mini.
Not exactly answering your question here, but if you use an encrypted partition then it won't matter to CCC, you can clone from an unencrypted partition onto an encrypted partition.

I've not tried backing up into a disk image with CCC so I can't answer the actual question.
 

sparkie7

macrumors 68020
Original poster
Oct 17, 2008
2,037
106
Apple supports full disk encryption on Lion and newer (works the same way as FileVault2) so you can just encrypt the whole disk. In Disk Utility you partition the disk and choose "Mac OS Extended (Journaled, Encrypted)". Then whenever you plug the disk in it will require a password to unlock (you can save this on your computer so it's unlocked automatically if you want).

This should be a better alternative to encrypted disk images, unless you need it to work with computers running Snow Leopard or older.
Thanks. But yes, I am on an older system and prefer to be b/c of Rosetta and running old PowerPc applications.

Not exactly answering your question here, but if you use an encrypted partition then it won't matter to CCC, you can clone from an unencrypted partition onto an encrypted partition.
Ok thanks. But I assume one has to open and unlock the encrypted Disk Image first in order to be able to clone to it?
 

maflynn

Moderator
Staff member
May 3, 2009
65,900
32,236
Boston
Ok thanks. But I assume one has to open and unlock the encrypted Disk Image first in order to be able to clone to it?
No, I believe you'd just need to copy the DMG to the drive. When its done, to mount it, you enter its password.

Try it on a small DMG and see if it works to your expectations
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
29,978
9,615
California
I have ordered a 1TB G-Drive Mini to back up all my photography files. As this drive will be mobile or left in a different location to home and work I would like to protect it. So thinking a password protected Disk Image might be the way to go.

As far as I know, Apple does not offer any software to protect an external drive or volume. ie. like a Password to open and mount the drive. So is an encrypted Disk Image the way to go? And is 1TB ok, or is it too large?

At the moment I have a 1TB partition on a 3TB Hitachi internal drive in my Mac Pro where I store all my photography files. But wondering now that when I want to clone it using CCC to this 1TB Disk image will it still work ok? ie. my source drive/partition is not a Disk Image. Do I need to back this up. Wipe it and create a 1TB Disk Image (or say 990MB Disk Image as 1TB is too big as it needs other system files also) and THEN clone this to my G-Drive Mini.

Or can I leave the Source partition alone. Then create a Disk image on the G-Drive. Then when I want to clone it, mount it. Then open CCC to clone to the Disk image. Hope this make sense. Which option is better?

Any advice, suggestions on how to set this up appreciated.
CCC can do all this for you. Just leave the files as they are on the internal. Erase the external and format in Mac OS Extended. Then start CCC and pick the internal 1TB as the source. On the right where you select the destination click the drop down and pick New disk image... then configure it as a read/write sparse disk image and pick the encryption option in the bottom drop down. Select your external drive as the location for the disk image.

This will cause CCC to make a new, encrypted sparse bundle image on your external drive and it will clone your photos inside the image. You don't need to make or manage any encrypted disk image yourself at all. CCC will handle it.

After the clone CCC will dismount the disk image. If you want to access files in the image just double click the disk image in Finder and you will be prompted for the password. When you are done looking inside the image in Finder just eject the disk image. You don't need CCC to open the image and use it.

Then next time you clone photos with CCC, CCC will open the encrypted image (password is optionally saved in OS X Keychain) and add changes to the image.

By using a sparse bundle the disk image will expand on its own only to the size needed to contain the photos. So if you have 350MB of photos, the image will only be 350MB. If more photos are added and you now have 400MB of photos, the image will expand on its own to 400MB.



 

sparkie7

macrumors 68020
Original poster
Oct 17, 2008
2,037
106
Awesome THANKS Weaselboy ;) I didn't know you could save as a Disk Image inside CCC. Thought only Disk Utility could save disk images etc, let alone encrypted.

I assumed previously that I had to open and password open the disk image in order to be able to copy/clone to? But sounds like it can be handled all in CCC? I have version 3.4.7, is this version capable of the above in your post?

Also what is the largest conceivable dsik image I can create on a 1TB drive?

The other disadvantage I presume or can think of is that if you have a boot system on the disk image -- then it won't start up or be selectable as a start up disk?

Thanks again :D
 

sparkie7

macrumors 68020
Original poster
Oct 17, 2008
2,037
106
No, I believe you'd just need to copy the DMG to the drive. When its done, to mount it, you enter its password.
But I still need to clone or periodically update backup every week or two. So each time I'd have to unlock the disk image on the target drive to be able to copy to it?
 

gnasher729

macrumors P6
Nov 25, 2005
16,690
3,381
But I still need to clone or periodically update backup every week or two. So each time I'd have to unlock the disk image on the target drive to be able to copy to it?
No, you don't have to unlock the disk image to copy it. The disk image itself is a normal file that can just be copied. It's like transporting a safe - you don't need to open it to transport it.
 

Dark Dragoon

macrumors 6502a
Jul 28, 2006
843
3
UK
But I still need to clone or periodically update backup every week or two. So each time I'd have to unlock the disk image on the target drive to be able to copy to it?
Well it depends on whether you want to copy the entire disk image each time you want to back it up (even if only one or two files have changed), which may be up to 1TB in size.

Or whether you just want to update the contents of the disk image used to backup the files, with just the files that have changed.
 

sparkie7

macrumors 68020
Original poster
Oct 17, 2008
2,037
106
Well it depends on whether you want to copy the entire disk image each time you want to back it up (even if only one or two files have changed), which may be up to 1TB in size.

Or whether you just want to update the contents of the disk image used to backup the files, with just the files that have changed.
Yes, the later would be preferred. More efficient. So all I need to do is unlock the disk image on the target drive then launch CCC and clone across with update?
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
29,978
9,615
California
Awesome THANKS Weaselboy ;) I didn't know you could save as a Disk Image inside CCC. Thought only Disk Utility could save disk images etc, let alone encrypted.

I assumed previously that I had to open and password open the disk image in order to be able to copy/clone to? But sounds like it can be handled all in CCC? I have version 3.4.7, is this version capable of the above in your post?
Yep... 3.4.7 has this.

Also what is the largest conceivable dsik image I can create on a 1TB drive?
If, hypothetically, your cloned data grows to 1TB, then the sparse bundle will automatically expand to the full 1TB until it can't grow any more due to the partition size. The nice thing about sparse bundles is they grow up only to the size of your data inside the image.

The other disadvantage I presume or can think of is that if you have a boot system on the disk image -- then it won't start up or be selectable as a start up disk?
Yes, that is a downside, but there is a bit of a work around. CCC will put a copy of the recovery partition on your backup drive. So if you need to restore a CCC clone to a new drive you would option key boot to the the recovery partition on the external drive, then use Disk Utility from there to "unlock" the encrypted image. The use Disk Utility to restore the clone back to the new internal drive.

So you cannot directly boot to and run off a bundled clone like you can a regular CCC clone, but you can use that clone to restore a system to a new drive say after a drive replacement.

Thanks again :D
You bet... glad to help.
 

sparkie7

macrumors 68020
Original poster
Oct 17, 2008
2,037
106
Yep... 3.4.7 has this.
Ok great.

If, hypothetically, your cloned data grows to 1TB, then the sparse bundle will automatically expand to the full 1TB until it can't grow any more due to the partition size. The nice thing about sparse bundles is they grow up only to the size of your data inside the image.
That's a useful feature. Is this sparse feature on Disk Utility and CCC as a stand alone option, if one want to create a sparse disk image with a starting size but that can grow/expand as needed?

Yes, that is a downside, but there is a bit of a work around. CCC will put a copy of the recovery partition on your backup drive.
Sorry, please clarify what will CCC copy on the recovery partition?

So you cannot directly boot to and run off a bundled clone like you can a regular CCC clone, but you can use that clone to restore a system to a new drive say after a drive replacement.
Ok, thanks again for all your help!
 

DeltaMac

macrumors G3
Jul 30, 2003
9,893
2,522
Delaware
... CCC will put a copy of the recovery partition on your backup drive. So if you need to restore a CCC clone to a new drive you would option key boot to the the recovery partition on the external drive, then use Disk Utility from there to "unlock" the encrypted image. The use Disk Utility to restore the clone back to the new internal drive.
...
OP has Snow Leopard - which has no recovery partition…
Does CCC somehow create one?
 

Similar threads

Replies
2
Views
425
  • steve23094
9
Replies
9
Views
2K
  • Eneco
2
Replies
2
Views
792
  • Hat Tric
2
Replies
2
Views
907
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.