10.3 Removing Unneeded Versions from a VOB

Scrubbing only removes artifacts that can be regenerated. Scrubbing never removes versions of elements. Because elements and versions are historical data, you should approach their removal with extreme caution. Removing entire elements, using rmelem, is particularly dangerous:

• Even if an element is no longer needed for ongoing work, you may need it to reproduce and maintain earlier work.

• rmelem removes the element's name from all directory versions in which it was ever cataloged. This erasing of history means that the element does not appear in listings or comparisons of old directory versions. Removing an element's name from a VOB directory, using the rmname command, preserves its history but makes its name invisible in subsequent versions of the directory.

• Making a mistake can be costly; there is a procedure for recovering from backup an element that was deleted mistakenly, but it's cumbersome. (See Restoring an Individual Element from Backup.)

If you need to reclaim disk space, it is more prudent to remove individual versions of elements, rather than entire elements. The rmver command makes it easy to remove versions that you believe you will probably never need again.

By default, rmver removes only versions of little use:

• Versions that are unrelated to branching: not located at a branch point and not the first or last version on a branch

• Versions that have no metadata annotations: version labels, attributes, or hyperlinks

You can also use the cleartool relocate command to move entire VOB directories and all the element versions they contain from one VOB to another. Chapter 14, Splitting VOBs with relocate, has more information on this procedure.