Clearvision CC2SVN is an asynchroneus synchronisation service that synchronizes two version control repositories automatically.
It is a commercial product, at the time of writing it costs GPD 1100 for 1 server plus 10 bridges. The cost of 1 server & 50 bridges is GPD 1800.
A bridge is their term for the connector between one ClearCase branch in one ClearCase VOB and one location in a Subversion repository, i.e. between svn/repository/trunk and /view/vob/ where view designates which branch to monitor for changes. So you could configure multiple bridges for multiple branch <-> location pairs in the same repository (vob <-> svn-repository ).
The same product is about to be supporting GIT repositories too, but the feature is still in beta and will naturally have a cost. I have not (yet) tried the Git bridge.
I have been investigating this on a Windows XP machine with ClearCase 7.0.1 installed and SVN command line client.
In order to install there are some prerequisites: supported OS (Windows/Linux), a ClearCase client install, a Subversion command line client, CC2SVN - and a license. If you register at Clearvision's site you can register and then request a trial license.
You can have the ClearCase server install, the Subversion server install on the same machine as CC2SVN, but you don't have to, only the clients are needed.
The CC2SVN installation itself is simple, during install it offers - or insists on sending a license request form to Clearvision via smtp, so you could be needing to know a smtp mail host. If you deselect the email client during installation you can get around that, without sending the mail. For production use an smtp mail is mandatory - because that is the way the tools will notify about conflicts or any other problems.
Before you are ready to configure the first bridge, you are required to prepare both repositories, the vob needs a specific attribute type to created, and the svn repository needs 2 hooks. And then you need to finalize the CC2SVN configuration file, with information about CC2SVN working directory.
Then you should create a ClearCase view - handling a branch that is designated to use for the synchronization (that simplifies the task of cleaning up, if anything undesired occurs). And start the view on you CC2SVN server - ah, note to self - ONLY dynamic views are supported. Don't forget to mount the vob too.
From the SVN side you need a checkout of the the location, you want to be synchronize. When starting to use CC2SVN the most common story are that you are creating a copy of a code base from one system to the other, so you could say that at that time - when the synchronization is started one system is master, and sends the code to the other system or repository. After the initial sync neiter system is master, and once every 60 seconds - or whatever you write in the config file - both ends of the bridge is checked for change, and if any they are send to the other end.
When all the above prerequrequisites are in place you are ready to start the CC2SVN servers. One server is the daemon checking for changes at an interval - the other server is only for configuring and maintaining the bridges.
And that was where I had to stop, as this was a time boxed task. I had the vob & view configured and running, the svn repository prepared and the 2 CC2SVN servers running.