About Feature Levels and ClearCase

Technote (FAQ)


Where is the information pertaining to new features and what are some of the high level changes made to the currently supported versions of IBM Rational ClearCase?


An overview of feature levels is available in the ClearCase Information Center under the topic of Overview of feature levels.

Information on how to raise the feature level of a VOB is available in ClearCase Information Center under the topic of chflevel or you can run cleartool man chflevel from the command line.

Feature levels can only be raised to a higher feature level and cannot be lowered.

For specific directions about raising the feature level of MultiSite VOBs, refer to Deploying Rational ClearCase under the topic of Feature Levels.

Below is a consolidation of the high level features from each release.


ClearCase Feature Levels

The Feature Level of a VOB dictates what features and or enhancements are available when working in that database.

A feature level is an integer that is incremented at each ClearCase family release which introduces features that affect the way data is stored in VOBs. The purpose of having feature levels is to prevent the use of new features which are not understood by client hosts with an older ClearCase version installed. Features and/or functionality protected by a new feature level are not supported with clients using older ClearCase releases. VOB feature levels should be raised only after all client hosts have been upgraded to the corresponding ClearCase version.

Once the conditions for raising the feature level have been met, IBM Rational recommends raising the feature level of all associated VOBs at the same time. An operation that affects multiple VOBs at different feature levels may produce unpredictable results (for example, a UCM project VOB (PVOB) and its component VOBs, or an Administrative VOB (AdminVOB) and its client VOBs).

The feature level of a VOB is initially set at it's time of creation. Except as noted below, the feature level will default to the highest feature level supported by the ClearCase release installed on the server. For instance a new VOB created on a ClearCase 8.0 server will be created as a feature level 7 VOB as you can see from the table below. Exception: For VOBs created on ClearCase and later 7.1.2.x fix packs the VOB feature level will default to 5.

This table lists the ClearCase release in which a new feature level was first introduced.

Note: A feature level will continue to be supported in newer versions until IBM Rational announces otherwise in the Release Notes.

Feature Level
Introduced in release
Support dropped in release
Refer to the IBM Rational Administrator's Guide under the topic of "Feature Levels" in the ClearCase Information Centerfor further information.

Overview of current features:

Feature Level 8:

Raising the feature level to 8 introduces the following features:

Introduces ACLs (Access Control Lists) to control access to VOBs.

Feature Level 8 also changes mkelem/mkdir behavior for the new element's group, as explained in the info center 'mkelem' reference page. At Feature Level 8, the element group is copied from the containing directory's group, rather than from one of the user's groups.

Reference Version 8 mkelem documentation

Feature Level 7:

Raising the feature level to 7 (or in the case of a replicated VOB, raising the replicated VOB family to feature level 7) introduces the following features:

  • Evil twin detection and prevention
  • Support for additional integrations with Rational Team Concert
  • Predefined element types for Unicode type managers
  • Improved UCM Performance
  • More precise event time storage during checkin and checkout

Feature Level 6:

Raising the replicated VOB family to feature level 6 results in the following changes in the VOB:

  • Introduces new Synchronous Request for Mastership (SRFM) functionality which allows a user to request mastership during a checkout operation. Refer to technote 1470733 for further details.

Feature Level 5:

Raising the feature level to 5 (or in the case of a replicated VOB, raising the replicated VOB family to feature level 5) results in the following changes in the VOB:

  • A VOB at feature level 5 is able to contain elements that are larger than 2 GB.

  • A UCM project in which the PVOB and all component VOBs are at feature level 5 can take advantage of improvements in several UCM operations.

    For more information, review the ClearCase 7.0 release notes on the topic of Improvements in Unified Change Management (UCM)

  • When a replica family is at feature level 5, replication becomes more efficient in cases where the -maxsize option is used with syncreplica.

Feature Level 4:

Raising the feature level to 4 (or in the case of a replicated VOB, raising the replicated VOB family to feature level 4) results in the following changes in the VOB:

  • Feature level 3 placed constraints on client/server compatibility in UCM environments. Feature level 4 introduces no additional constraint; it is equivalent to feature level 3 in terms of PVOB client/server compatibility. Also note that read-only streams and single-stream projects are restricted to PVOBs at feature levels 3 and higher (see the reference page for mkstream).
  • Permission preserving replication mode was introduced for MultiSite between Feature level 4 and higher VOBs. Related technotes: make branch operation may fail and set preserve perm not valid .
  • The predefined element types xml, html, and rose (if they exist) are renamed to xml_v5.0, html_v5.0, and rose_v5.0, respectively. Similarly, element type names that you have changed are renamed to name_v5.0. The v5.0 types lose their status as well-known element types. Accordingly, when you create new elements, the file-to-type mapping mechanism no longer treats these types as the defaults (see the cc.magic reference page). The type of an existing element does not change; however, you can use chtype to change it.

  • The new predefined element types xml, html, and rose are created. The purpose of replacing these types is to base the type managers on the binary_delta type manager instead of the text_file_delta manager. The cc.magic file maps new elements to these types by default.

  • The element type, xde, is created.

As of Rational ClearCase 2003.06.00, Rational ClearCase Attache is no longer supported.

Rational ClearCase 7.0 is the last major release to support VOB feature levels 0, 1, and 2.

Rational ClearCase 7.0 does not support VOB database schema 53. Review the ClearCase 7.0 Release Notes and technote 1201579 for more information.

Review the IBM Rational ClearCase MultiSite Administrators Guide on the topic of mkreplica (cleartool man mkreplica) for information about feature level restrictions related to creating new MultiSite replicas.

Related information

Raise the feature level of a VOB and not the server
A Japanese translation is available

Document information

More support for:

Rational ClearCase
Feature Level

Software version:

7.0, 7.0.1, 7.1, 7.1.1, 7.1.2, 8.0, 8.0.1

Operating system(s):

AIX, HP-UX, Linux, Solaris, Windows

Reference #:


Modified date:


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