I have looked for a solution to keep important work files always available. This means that they have to be usable from several computers, even at the same time. I usually use Linux desktop and Windows laptop at the same time.

The current option I am considering is Wuala (www.wua.la). But let’s check other alternatives I have tried first.

I have tested some synchronization software (e.g. rsync). I don’t trust them enough. If they decice that some file should be deleted I likely does not even notice it before it is too late. So there should be synchronization and backup. There are good solutions for Linux but not interworking.

Some of my computers are regularly behind NAT which means that I need an server in public Internet to sync all my computers.

I could keep everything in a Subversion repository (http://subversion.tigris.org). It is not an optimal solution for everything else except source files. It has logging but I still need to take care of backing up my server. Too much work for daily use of all the documents I handle.

Some text documents could be kept in Google Documents (http://docs.google.com). It seems to have some issues with Opera - I once lost an hour of edit although Opera said everything is saved. I have started to use more and more Opera and I want to be able to use it. And Google Documents can only store text and presentation files. I need a place to store associated PDF, source, binary etc. files as well. And it is not very fast to edit documents with JavaScript scripts.

I tried some document management systems installed to my own server. None of the Debian Linux easy-to-install packages didn’t seem to be satisfactory for this purpose. One I tried to install was Knowledge Tree Community edition (http://www.knowledgetree.com). I quite soon found a situation that would have required deeper debugging of the software and decided that I can not trust myself as an administrator for an system where I want my all important files to be stored. And backing up the MySQL database to another server over the network is not trivial.

To have a commercial service would be nice. They guarantee backups - if the don’t go into bankruptcy. To get an open format backup of this kind of service is even more difficult than getting backup of MySQL database of my own. If my business would be any bigger, SalesForce (http://www.salesforce.com) and associated NetDocuments (http://www.netdocuments.com) would be an interesting alternative. The companies have excisted already many years and feel reliable. The minimum is 3 users, $75/month for only the documents part. This is too much for a simple need.

My network operator would sell a large network disk much cheaper, 50G only 5 Eur/month. Local operator is a trustworthy partner where you know who to sue:-) The service is meant for web access - the files are available from the web and you must write them using non-encrypted FTP. Handy for www-designers, showstopper for me. I need much deeper integration, something like SAMBA over SSH.

So, the best alternative this far is Wuala. It is not perfect and it is Alpha, but is gives a promise to solve my problem.

Wuala is a distributed global disk. The technology behind is bit like peer-to-peer. The data is in their server but also additionally in the disks of other participants. When you need something, it is loaded where it is found. It is like peer-to-peer but faster because it is controlled bu master servers.

Wuala tries to guarantee privacy of the files. All the users and groups have their private password that Wuala company should not know.

Do not mistake this to documents that are marked "public". There you can find the usual peer-to-peer content.

Wuala is a Java program that works in Linux, Mac and Windows. In Linux it works better than most Java programs with the normal distribution problems (Debian-based Linux distributions can not integrate well Java software because of some fundamental flaws in Java environment design). There is no package and so you must install it yourself to Linux. I had no problmes, though.

I can drag-and-drop files to Wuala folder and access them from any of my computers. It is fast - it potentially transfers files directly from my one computer to another. Arranging files to folders is easy, familiar and fast (it is done in the local computer). Using Wuala is assumedly secure. Backup is trivial: just copy files to a folder in any connected computer.

The problems with Wuala is that it is still in Alpha. It is company supported, but what to do if the company disappears overnight? Likely, I can not access even my cached files if the server disappears (they are in an encrypted database file and the key is somewhere in the system). Privacy is OK in theory but how can I be sure that my closed-software client does not give my private encryption key to the server? I have some serious doubts of this. And the content in the public folders likely makes authorities want to break the privacy of the system sooner or later. In this situation, I’d appreciate automatic versioned backup of my files.

Wuala is still the best alternative I have found to share my working files in all my working computers. But, I don’t keep there anything sensitive and I keep manual backups.

Ceterum censeo Java esse delendam.