Image file for archival backup

[astrodog]

Hi there....
I've backed up a hard drive to a network drive using a sparsebundle, this is for archival purposes, so it won't need to be added to. Would I have been better off with a read-only image? I've read of issues with sparsebundles corrupting, and the big one I've made takes an age to mount and navigate.....

Where is all the extra space required during processing a read-only image supposed to be - on source or destination? The destination has heaps of space, but the source (a full hard drive) hasn't.
I've used disc images up to about 30GB before - any probs going to 300-400GB or so?
Cheers

[dnanian]

No, I'd use a read/write image/bundle. The extra space is because the image has to be created read-write, then converted read-only (on the destination).

[astrodog]

What's the advantage of the read/write over read-only?

For what I want - I may need to retrieve a file or two from the image occasionally, but if I need to do a bunch of work, I'd just restore it to a drive and work from that (on the image is really just raw video data from my camcorder).

[dnanian]

It doesn't require all that extra conversion I/O and can be updated.

[astrodog]

Thanks.... I don't need updates for these images, and when I start off a 400GB backup I usually go to bed anyway.... Does the read-only take significantly longer, or does it tie up more resources, or both??

I think I'll make one of each and take them for a spin, learn by doing!

[dnanian]

Yes, it takes much longer, and temporarily uses twice the disk space.

[astrodog]

Wow... just got home to see the read-only image I started this am, finished half an hour ago.... :)

383GB hard drive image - took 3hr 50min to create the sparse-image, then another 5hr 20min after this to complete.... glad I was at work!

It mounts in a second or two and is much faster to navigate than sparsebundles I have, then ejects in a split second too - is this normal??

I certainly won't use these for anything other than a record once, leave-as-is-archive type backup thats for sure (at this size anyway) :)

[dnanian]

Up to you, of course!