The statements below are all accurate, but I've added a couple of
clarifications below.

On 6/10/2010 11:23 AM, ghu wrote:

We are preparing a large scale migration from ClearCase to RTC SCM
using RTC's CC connector which contains two migration tools:
ClearCase Synchronizer and ClearCase Importer, and have conducted
full test on various scenarios based on the teams' need.

I'd like to share the results here and hope to get comments from those
who have tried it to see if we may have missed any:

If you just want to migrate the tip of the CC branches to RTC without
revision history data, then the ClearCase Synchronizer is useful tool
to get it done. You need to be aware that you'll need both the branch
type and a backstop label type to create the synchronization stream
to import the branch tip to RTC; and you can sync. changes between CC
VOB and RTC repository in both direction after the migration if you
want;

Note: If that branch exists on every element that you are
synchronizing, then no backstop label needs to be specified. In most
cases, you won't have that branch on every element so a backstop label
is needed (just check the config spec of a view that uses that branch
.... the backstop label will appear in that config spec).

If you want to import CC revison history, then you can use ClearCase
Importer which at 2.0.0.2 release, can let you import limited label
history.

Note that "limited label history" means "the list of labels that you
select" (you can select any list of labels that you want).

You need to know that the CC branch type is not used when
use this tool and that no revision history between the imported
labels are imported.

Note that no branch type is used because the versions imported are
exactly those versions selected by the label. So it is assumed that
there is a label on every element you are importing (including directory
elements).

Unfortunatedly the resulted RTC component
baselines are not mapped properly to the original CC labels yet and
will be available in 3.0 release.

In RTC 2.*, the CC baselines are mapped into RTC change sets. That
provides all the information you need to create the RTC baselines if you
want (just accept those change sets into a workspace, and create a
baseline). But this was a commonly requested feature (understandably
.... it's not all that amusing to go in and manually create baselines
:-), so in RTC-3.0, we now automatically create both a change set and an
RTC baseline for each imported CC label.

Overall, you will get a stream for each branch you import, and all
branches and labels imported from the same VOB will end up in the
same RTC component, enabling you to run merge between them later if
needed, a feature the simpler file system import from the CC branch
tip doesn't have.

We expect more features and improvement availabe in 3.0 release to
help us reduce the burden to run migration involving thousands of
branches and labels .

The synchronizer (and its "history importer" variant) are not intended
to transfer thousands of branches and labels from ClearCase to RTC. It
is just intended to bring over a small set of key release/integration
branches, and a (relatively) small set of key baselines/labels, so that
RTC users can work on the same code as ClearCase users (with some key
history available). Please see note http://jazz.net/library/techtip/68
("Deploying Rational Team Concert into a ClearCase/ClearQuest
Environment") for deployment guidance. We are investigating techniques
for bringing over greater amounts of labels and file history, but there
are no plans to do so in the 3.0 release.

Cheers,
Geoff

Thank you for detailed clarification. I conclude that there is no way to import all of the history into RTC. Is that correct? In this scenario, if the user imports Base ClearCase VOBs into RTC, are they able to bring over the owner, comments and time stamp information into RTC? Can this information be also available when you do annotate on a given element?

Thank you!

That is correct ... you can only import a user specified list of
baselines/labels ... not "all the history" and very little metadata. In
particular, no owner or time-stamp information is imported, and very
little comment information.

Since it is not brought over, it will not be available at annotate time.

Cheers,
Geoff

On 11/22/2010 9:53 AM, umangshah wrote:

Thank you for detailed clarification. I conclude that there is no way
to import all of the history into RTC. Is that correct? In this
scenario, if the user imports Base ClearCase VOBs into RTC, are they
able to bring over the owner, comments and time stamp information
into RTC? Can this information be also available when you do annotate
on a given element?

Thank you!