How would you migrate a multi-site ClearCase/ClearQuest environment to all Open Source?

Question

I work in an multi-site environment that's currently using Rational ClearCase for source control and Rational ClearQuest for issue tracking (I accept your condolences ahead of time). As a rough estimate I would say this is supporting 200 engineers.

How would you effectively migrate this SCM methodology to a comparative, all Open Source tool suite? Not only would this save literally hundreds of thousands of dollars but I also believe it would improve developer productivity and very little downtime compared to the current system.

Platforms in use include Windows, Linux, UNIX and Solaris.

Answer 1

Clearcase is awesome. I use to think like you but then after moving to perforce I realized how great dynamic views are.

I actually asked about this in another question. Basically it is really, really hard and is made much easier if you can live without your revision history.

As for bug tracking my experiences are that open source bug tracking tools are terrible. However using triggers it is usually very easy to integrate them with open source source control. As an example here is how to integrate bugzilla and subversion

Answer 2

First, why do you think this would improve developer productivity? I haven't used ClearCase much, and ClearQuest not at all. What about these tools is hindering development?

Once you know what you want, you need to look at various tools. I'm fond of Subversion for SCM, as a general rule, but there are situations it isn't well suited for. I have no strong feelings on specific version tracking systems.

Bear in mind that migration is likely to be a really big project, depending on what you want to bring over from the Rational systems (checking everything out in ClearCase and starting entirely new projects in Subversion will be easy, but any history you want to keep is a lot more work), so there will be no immediate dollar savings. Moreover, switching tools is going to reduce developer productivity for a short time (possibly very short), so this is best seen as a long-term move. Make sure you get the tools you want up front, since you aren't going to want to do migrations very often.

Answer 3

Condolences are not required, it seems that if you are working in a large scale development over more than one site, then you have the right tools for the job.

Attempting to make Open Source SCM products work over various sites will be a very interesting challenge - I've not seen something that will work securely, reliably and without a horrendous amount of work (though I'd love to be proved wrong!).

Although your licenses do cost a considerable amount, you also have access to the IBM tech support (who I've found very useful very often). How much would it cost if your open-source environment crashed to it's knees for some reason and your support network consisted of you and your colleagues? 200 developers unable to work effectively? Erk.

I'd be interested to hear why you think it would improve developer productivity. Do they have specific gripes? What do they find is an issue? Could we help you from here work it out with them?

In my humble opinion, Open Source tools are perfect for small to medium sized projects without a relative amount of complexity. I feel what you are attempting to do will be folly.

Answer 4

Does BasketCase cheer you up any? You might be able to modify, or at least abstract some of the environment you already have...

Answer 5

I've done migration from ClearCase base to Git using Gitcc. Worked like a charm.

Answer 6

As for any tools, ClearCase comes with advantages and drawbacks.
We only use it for lager project with complex merge workflow, where UCM is very useful to visualize in advance the different branches.

Right now, we are evaluating various DVCS open-source solutions, but in my opinion, they cannot handle all kind of projects (like the one with too many files).