What is Clusters?

Clusters is a tool for Snow Leopard (Mac OS X 10.6+) that takes advantage of a little-known feature introduced in that version of the OS: files can be stored in disk in a compressed format, thus taking less space. The beauty of the feature is you don't need to keep track of what files are compressed - the OS will automatically uncompress them for you whenever you access them. The system works so good that it's not easy to realize that all Snow Leopard built-in apps (Mail, Safari and the like) are actually compressed when you install the new OS!

At LateNiteSoft we thought it would be awesome to extend this capability to any of your files, and thus we created Clusters - a seamless, background compressor tool that uses Snow Leopard's HFS-compression mechanism to help you save disk space while getting out of the way.

How safe is it?

We have designed Clusters putting a lot of care on safety and reliability. Every file that needs to be processed is compressed to a temporary location, then verified before replacing the original one. Replacement takes place atomically, which means a valid file (either compressed or uncompressed) will always be created, even if the system power goes down in the middle of the process. Clusters will also check whether the file being compressed is being written to by another application, and will verify that its time-stamp has not changed since the compression process started - in those situations, compression of that file will be retried at a later time.

Nevertheless, Clusters is a system tool that deals with a large number of files, so caution is encouraged - as usual, we recommend to keep up-to-date backups of your system files.

How will Clusters affect performance?

During the compression process itself, Clusters schedules its work according to your system's CPU and disk activity, so as not to interfere too much with other tasks. You can also pause Clusters on demand, for those tasks that require all the CPU or disk throughput they can get.

For compressed files, there is no need to worry: even though the system needs to uncompress the files when reading them, smaller files means fewer disk accesses, so the two effects compensate each other to some extent. Also, keep in mind that many layers of cached data are kept by the system, so uncompression will not necessarily be performed each and every time you open a file. Specific metrics, of course, vary depending on the relative throughput of CPU versus disk performance in your system, as well as the typical size of files you use most.

A fresh install of Snow Leopard will store compressed versions of system applications in your Applications folder. Chances are you did not notice your applications starting up more slowly in a recently-upgraded Snow Leopard computer - in fact, our experience seems to suggest otherwise.

I am about to do some heavy CPU/Disk load work. Can I pause Clusters?

Of course. Simply select the Pause option through Clusters's icon in your menu bar. Note, however, that Clusters tries to be easy on your resources, and will throttle to adapt to your computer's load levels - thus, pausing or turning Clusters off should not be necessary in most situations.

I have just added new items but still see no compression taking place

In addition to Clusters throttling itself according to the current CPU and disk load in your system, Clusters will also wait a few seconds when it detects recent modifications in the files or folders it is about to compress. The rationale behind that is to avoid compressing files that are being used regularly, and that will need to be recompressed again if they are modified shortly after being compressed. All these factors can cause Clusters to progress slowly on occasion - Clusters is just waiting for the best time to do its job.

Finder shows no change in file size, how can I know if Clusters is working?

The compression technology in Snow Leopard is almost completely transparent: Finder will always report the uncompressed size of your files. The reason for that, we think, is to avoid confusion when copying folders to another location, which would show a different size in the destination since the OS uncompresses files when reading or copying them.

In order to check the real savings, you can look at the total free disk space figure in any of your Finder windows. Clusters will also report all historical savings it has achieved; however, keep in mind that savings will be accumulated when files are compressed several times.

You can also see the details of disk usage using the command-line "du" in Terminal. In order to do so, please open a Terminal window, then enter the following command, replacing folder_name with the name of the folder you are interested in: du -sh folder_name. This will show the exact space taken up by that folder, with the catch that the units are referred to a binary base instead of a decimal one (1 KB = 1024 bytes, as opposed to the new convention in Finder, where 1 KB = 1000 bytes).

There are some files that Clusters never compresses

Clusters will ignore certain files that would probably achieve no savings when compressed. This is the case for compressed media formats, or zip and rar archives. Clusters exclusion rules also include system locations such as caches, libraries or the system kernel itself. Also, Clusters will not use administrator privileges, so it will not attempt to compress files it does not have access to.

In addition, Clusters will stop compressing a file when its compressed size (not the original, uncompressed one) is larger than 2 GB - this is a limitation of the compression technology Snow Leopard provides. In this situation, the original file is kept, and compression is never attempted on that file again.

I have uninstalled Clusters. Will compressed files still work?

Absolutely! Clusters simply converts files to the compressed format understood by the Snow Leopard implementation of HFS - from that point on, it is the Operating System itself that deals with the file, uncompressing it for you on the fly whenever you need it.

What kind of folders should I select to squeeze?

We recommend you select folders where usage is heavier on reading but lighter on writing. In addition, folders with music, movies and pictures are not good candidates to compress, as they are already compressed in most cases. Excellent candidates are your Applications and Documents folder.

Will compressed files work on machines not running Snow Leopard or Lion?

Yes, unless you access them directly (for example, turning off the Mac, taking out the drive and installing it in a different machine). All other means should work fine (email, dropbox, copy to a pen drive, copy to an external drive, etc.). This is because when you copy a compressed file to any location in the disk, the system will create an uncompressed copy.

How can I uncompress a file?

Simply copy it using the Finder. The copy will be an uncompressed version of the file. Make sure, however, to copy it into a folder that is not being watch by Clusters, so it does not compress the copy, or pause Clusters for a moment while copying the file. You can also use Clusters' built-in uncompressor, which is located in the "Exclusions" tab of the preference pane.

I use File Vault. Is Clusters compatible with it?

Yes. However, because of the way File Vault operates, your gainings will not be realized until you log out and login again (or you reboot your machine).

Is Clusters compatible with Hazel?

It is, since version 1.0.2.

In previous versions there was a cyclic incompatibility with Hazel and, potentially, other background filesystem tools. Files compressed by Clusters triggered file system notification events that, when received by Hazel, caused it to uncompress the files again. There was no risk of information loss, but files would cycle between compressed-uncompressed states.

In addition, Hazel performs file locking using a read-only mechanism since version 2.3.6, thus inadvertent uncompression of HFS-compressed files should no longer occur.

Is Clusters compatible with Time Machine?

Yes. Time Machine will have no problem in backing up compressed files. However, there is one inconvenient. After Squeezing files, Time Machines detects that the, now compressed, files have changed and makes a new backup for them. So, your newly compressed folders will be completely backed up again. We are looking for a way to improve this in a future release.

Why can't I compress the /Developer folder?

Apple recommends not to deal with the contents of that folder, and we honor that request. As a matter of fact, we did test compressing it, and while Xcode and the other tools work great, we found some weird behaviour whereby the iPhone Simulator would not launch applications when certain device / SDK combinations were selected, so we decided to play it safe. Note, however, that development documentation (the area that could benefit the most from compression) is already packaged in a compressed format.

What payment methods are available?

Payment services for Clusters are handled by FastSpring; thus, Clusters is available using any of the many payment alternatives they support: a variety of credit cards, PayPal, money orders, checks and others, depending on your location.

Registration does not work

Clusters needs access to the Internet in order to download the license associated to your license code. This is only necessary once at registration time. If you use LittleSnitch or any other proxies/firewalls, please make sure you allow this one outbound connection when you are trying to register.

What does the license give rights to?

Based on the usage you give to the license you can install it in a different number of computers:

  • Personal use: A license can be used on all computers owned by the license owner or where the license owner is the primary user.
  • Professional use: A license is required for each user, even when the license owner owns all the computers.

I have lost my license details

You can have it resent using this page, or contact us and we'll try to locate it for you.

I want to make a feature request.

Sure! Please, contact us and let us know. We are committed to continuous improvement of all our products, so we really appreciate your feedback.

I need to report a bug.

We are sorry you found an issue. Please, contact us and we'll work on a fix.