"Fog can be considered a type of low-lying cloud," says Wikipedia [1], and who are we to argue; this definition sort of sums up the ambivalent nature of the whole cloud hype and the related services. The success of cloud file sharing and synchronization services like Dropbox leaves room for alternative offerings and projects, which are popping up like the proverbial mushrooms.

Dropbox, but Self-Managed, Please

What all these services have in common is that users transfer their data to a third party for fiduciary management. Most cloud services today only share the means of transport and entice users with partially free, or at least extremely convenient, offers of access to data from anywhere, along with the ability to share data with others.

The realization that this is not always a good idea started to mature when risqué images of celebrities began to emerge from the cloud. Additionally, the passion of government intelligence services for collecting data is virtually infinite. The affirmation of "We're the good guys" is always relative to the speaker's intent.

Nine Clouds and Two BitTorrents Compared

Hosting your own cloud is a potential answer to diverse dependencies. In this article, we examine software designed for private users and corporations. The minimum requirement our test team stipulated was that the software offered basic file sync mechanisms and at least partly allowed the user to control the transfer of data – that is, anything under the "Filesync and Share" (FSS) umbrella.

The following comparison starts with ownCloud and then presents eight alternatives (in alphabetical order) that provide similar services for Linux users. It also looks at the peer-to-peer-based approaches of BitTorrent Sync and Syncthing. Table 1 shows the main features, and the box "Anecdotes from the Cloud" gives you three tips from the cloud admin's daily grind to help you manage your own cloud – no matter which software you choose.

ownCloud

ownCloud [2] (Figure 1), developed in 2010 by Frank Karlitschek, is one of the most popular representatives in the DIY cloud software field. The modular design of the software suite, which is based on PHP and SQL databases, offers much more than just file synchronization and sharing capabilities, with numerous apps extending the functionality.

Figure 1: ownCloud – the Enterprise version is shown here – is adaptable to a wide variety of needs.

This universality may have been one of the reasons that the developer resources were distributed across too many features and that a weakness (in the form of the initially often-criticized, poor FileSync performance with large amounts of data) went unresolved for many moons. Indirectly, the developers even aggravated this with nominal support for SQLite as the database back end.

Users also reported problems with the sync clients. The developers were well aware of this, which explains why they postponed additional features, such as sharing via the desktop client or binary delta sync – which enables an efficient transfer of very large files, to focus on improved core functionality.

The current version 1.7 of the client, which as of writing is still beta, does add the eagerly awaited overlay icons, for example, that help the user identify in the file manager which data was shared. One major benefit of ownCloud is the almost infinite number of additional applications, which stem to a great extent from the strong community. The administrator of the ownCloud instance decides whether to use them. You can thus put together a customized package for use in the enterprise. You can even create your own extensions, for example, to map workflows, using an app.