Using Sparse Bundle Images in Mac and Sharing them in Dropbox
Apr 27, · A sparse bundle is sparse in the sense that its disk storage grows (up to its set limit) to accommodate what you store in it. Common sense would suggest that sparse bundles also shrink as contents are removed from them, but APFS sparse bundles don’t work according to common sense. May 09, · A sparse bundle is essentially the same thing, the only difference is that while a sparse image is one giant file on your disk, a sparse bundle is actually lots of small files (8 megabytes each). They work and look the same way, but you can right-click on a sparse bundle, select "show package contents" and see the individual 8 meg "bands".
In this article, we will discuss one way of sharing sensitive information over the Internet. Encrypting images on a Mac and sharing them with Dropbox is a popular way of sending files over the Internet. Disk images adjust their size according to the space required by the files they contain. In other words, their size is dynamic, what is a sparse bundle can be an advantage when using file-sharing solutions like Dropbox.
Images can also be encrypted, another advantage when using Dropbox. The downside is that this how to unspoil a child of image is only compatible with Macs. There are many tutorials on the Internet on how to create this type of file. Basically, it works as follows:. This procedure results in an encrypted image in which we can store files of up to MB. The disk image will be automatically mounted. To unmount an image volume, just click on the Eject button to the right of the volume name, in the sidebar of the Finder window:.
To mount a disk image, simply double-click on the spiria. Or, type the following in the terminal:. After a while, a disk image will tend to fragment. Disk images are cut up in blocks, and these blocks are not always optimally filled as the disk image gets used. To reclaim this wasted space, unmount the disk volume, then use the following command:. This non-destructive operation is risk-free. Use the following command:.
This allowed me to enhance my filing and to avoid deleting files by mistake. This operation was very easy before El Capitan OS For some strange reason, the partitioning function of the disk utility no longer works with sparse bundle images. Proceed with caution: the disk partitioning procedure is destructive!
All data contained in the disk image will be lost. The best way to put a disk image in Dropbox is to mount the disk on the working Mac, do the work, then unmount the disk. This forces syncronization with Dropbox and ensures that other Macs will work with the latest version. Stray from this best practice at the risk of creating Dropbox syncronization conflicts, which must then be resolved.
Before resolving these conflicts, look at the structure of the image. To see the contents of a sparse bundle, you must show the contents of the package by right-clicking on the spiria.
To create a conflict, simply ignore everything that has just been said. How to keep wrens out of bluebird houses is my sure-fire way of creating a conflict:. At this point, you should make a copy of the disk image before attempting to solve how to draw a hallway in one point perspective conflict.
To do so, unmount the disk image and go to the bands directory see how to access it above. Since we want to recover the Wardell Mac version, we need to replace the files which conflict with the Wardell files.
We must replace ALL conflicting files, since we do not know how the image and the bands directory files match up. This time-consuming, painstaking process can get you out of a desperate situation. After replacing the files, mount the disk image, recover the file and copy it in the right disk image, i. Spiria home page. Blog and discussions. Enter your keyword When autocomplete results are available use up and down arrows to review and enter to select.
Creating a sparse bundle image There are many tutorials on the Internet on how to create this type of file. Basically, it works as follows: Open Disk Utility. Create a new blank image see screen shot above. The full name of the disk image is therefore spiria.
Or, type the following in the terminal: hdiutil mount spiria. Reclaiming free space in existing sparse bundles by recompacting files: After a while, a disk image will tend to fragment. To reclaim this wasted space, unmount the disk volume, then use the following command: hdiutil compact spiria. Use the following command: hdiutil resize -size m spiria. All data contained in the disk image will be lost The best way to put a disk image in Dropbox is to mount the disk on the working Mac, do the work, then unmount the disk.
Voluntarily creating version conflicts in Dropbox To create a conflict, simply ignore everything that has just been said. I also remount the disk image on Colombo. I unmount the disk image on Wardell. I unmount the disk image on Colombo. I let Dropbox syncronize… I remount both disk images. Solving a sparse bundle image version conflict in Dropbox: At this point, you should make a copy of the disk image before attempting to solve the conflict.
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Creating a sparse bundle image
Jun 15, · If you think about it, the new sparse bundle has to be created and the complete contents of the old one must then be copied across. Like copying a file, if you overwrite the original there’s no data to copy to the new one. Howard. Like Like. 5. EcleX on June 16, at pm. Sparse bundle disk image is an optimized form of the sparse disk image. It optimizes intentionally to reduce network load upon backup of changes to the filesystem at the expense of time and space. Specifically it uses a hashing function to store bits of data across a large directory structure which allows changes to be isolated in smaller band files. A Sparsebundle is a disk image format introduced by Apple in OSX as a method of effectively using space for backups on a disk. This is an expandable/retractable disk that will only take up as much room as the data inside of it up to a predefined limit (in the case of TM, the size of the partition).
A disk image is just a file which can be loaded into memory and function as a whole disk, with volumes, folders and more. Make a 1 GB disk image, and it requires a little more than 1 GB on disk. Far more efficient are sparse versions, the sparse image a single file and sparse bundle a structured folder pretending to be one file. This article looks at sparse bundles in Catalina A sparse bundle consists of a folder, the bundle, with the extension.
Inside that is an Info. As a minimum, there are two numbered bands, but these can grow into as many as needed to contain the files stored in the sparse bundle. Each has a maximum size of 8. There are two methods to create and maintain sparse bundles: using Disk Utility where its features work , and the command tool hdiutil in Terminal. Creating a new sparse bundle is well-supported by Disk Utility using the New Image… command in its File menu.
The minimum size depends on the file system selected in the Format section of the drop-down sheet: APFS has a minimum size of 8. Encryption options are set here. Ensure that you select the Image Format as sparse bundle disk image before clicking on the Save button. Although sparse bundles grow and can shrink in size on disk, the Size chosen here determines their maximum storage capacity in use. When you save your empty sparse bundle, it has a minimum size of 8.
For example, an empty 1 GB sparse bundle requires To use your empty sparse bundle, double-click it to mount, then use it as a normal storage volume. You may experience a strange interface bug in Finder when copying files to it, which can leave unfilled progress circles for some of the files being copied, even though their copying is complete. This has been present since Mojave, I believe, and might mislead you into thinking that the files are still being copied.
If you eject the sparse bundle and mount it again, they should vanish. One of the strangest and most irritating bugs with sparse bundles in APFS format is the unreliability of their estimates of size and free space. Whether you look at free space shown in the Finder or in Disk Utility, there is no correlation between what is shown and what is actually available for use in the sparse bundle.
For example, the smallest APFS sparse bundle allowed is 8. Catalina shows two different types of error when you try to copy what it feels is too much to your sparse bundle.
Sometimes, the new file is also created in the sparse bundle but abandoned there with zero size. A sparse bundle is sparse in the sense that its disk storage grows up to its set limit to accommodate what you store in it.
Even after you have put the entire contents of your sparse bundle in the Trash and emptied it, its size remains unchanged. The only way to perform this basic housekeeping task is to eject the sparse bundle and resort to Terminal, using the command hdiutil compact myDocuments. Output following that should resemble Starting to compact… Reclaiming free space… Finishing compaction… Reclaimed Compaction can be so successful that it reduces the size of the sparse bundle to smaller than when it was originally created.
That sounds like magic, or inefficient use of space in the first place. The maximum size of any sparse bundle is determined when it is created, but can be changed either up or down later when you wish. Thankfully, that claim is completely untrue, but has to be performed in Terminal. Before resizing, ensure the sparse bundle is unmounted then check the limits imposed on it using the command hdiutil resize -limits myDocuments. Then enter a command like hdiutil resize -size 20m myDocuments.
At least one bug has been fixed in working with sparse bundles over the past year. I bring one disappointment, though. In this article , I wondered whether the sparse bundle format used error-correcting code to improve resilience against corruption. Sadly, I can find no evidence of that from looking through the storage bands inside sparse bundles. Instead, they contain a lot of unused space, frequent repetition of similar data structures which might even amount to redundancy, even a hidden EFI volume, which enable them to withstand substantial amounts of corruption across much of their length.
But if any of the file system structures within the bands are damaged, the sparse bundle will be irrevocably broken. Despite their widespread use and advantages, macOS features supporting the use of APFS-format sparse bundles are at present riddled with bugs I count 6 above and have serious shortcomings.
Disk Utility remains of early beta-test quality and far from complete. You can only do that with hdiutil. But use too many of those, and the hdiutil command will crash. So in a corporate setting it might be better to create an intermediate certificate for your team and use the -cacert option instead of -pubkey and individual leafs… or create one leaf certificate incl.
Like Liked by 1 person. Thank you. Like Like. If you have opened a bundle in the cloud, unexplainable access takes place every few minutes. A single bundle brings together several hundred MB of traffic a day. In the cloud age, I would have expected more usability here.
With a large image, that could exceed your bandwidth! Thanks for the detailed article, Howard. The numerous bugs and gotchas you describe might be enough to send me running away from sparse bundles which I have no experience with as fast as I can.
However, I have a few questions…. In general, is the encrypted. For example, as far as I can recall, the sparse image never shrinks at all even when I delete a significant number of files, it can only grow bigger. Are the bugs in general the same? My main OS is still Mavericks Sparse images should work much the same, but use a single file for storage rather than a bundle with its bands.
Images and bundles have their pros and cons. In general, I think the advantages of bundles are greater, unless you want to move them to other file systems, when having a single storage file can make life a lot simpler. BTW, you asked us to report about this: I created a full TimeMachine remote backup on Catalina three days ago and it seems to have proceeded and finished without a real problem.
Some details: The host machine is a mac mini running Catalina The backup stopped after the main HD was completed. The second backup an hour after the first ended picked up the GB SD Pro card I have plugged into the iMac for infrequently used large file storage. Anyway both these two runs were without incident, and the result looks legit.
And is surprisingly performant given that I browsed it over the network from slow drives; a welcome surprise given how fast the Time Machine view has been in the past. But of course this was Mojave to Catalina. Maybe the problem is Catalina to Catalina, and the issue is with the backup client code, not the backup server code? This is a second tier backup, run once a week; basically a way to get some final value out of a few drives that are 10 or more years old, until they finally give up and die on me.
Normally, TM in Catalina backs up all the volumes set to be backed up in one session. Well done! Thank you for this in depth article about sparse bundles. I use disk images a lot for archiving purposes.
Sparse bundles could be a nice way to make online backups more efficient. Is that correct? Using Disk Utility has become somewhat of a lottery. Cannot find answer related to encrypted sparsebundle DMG,s. Whats actually encrypted? The container only? The files placed in such container are encrypted or plaintext?
I continue to use encrypted sparsebundles because they perform well and are nicely integrated. I have had very good performance even doing things like watching videos, etc on very old macs. I can even use SMB file sharing and then mount a bundle remotely. But I also worry about my data in them. They are very much not encrypted and I worry about them breaking or being corrupted. I mount the bundle then run the backup script. I keep an encrypted copy of the rclone config in my password manager if I need it for recovery.
It is a nice way to backup the otherwise hard-to-backup bundles. Hi, I think savings bundles are safe. The only corrupt bundles that you read about can be traced back to replicated TimeMachine backups via raspberry. For local savings bundles I use Duplicati and mount the bundle via a small script before starting.
Can I search for sparse bundles in terminal? Have you tried searching for directories with the extension. If you need to check deeper, look for the bands folder inside them.
I can find them with Finder, but then I have to manually get the path with get info.
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