Missing and unreferenced data containers

checkvob works to reconcile the contents of VOB storage pools with the information in the VOB database. This reconciliation requires checkvob to categorize data containers based on their relationship to this information.

checkvob recognizes two categories of data containers:
  • Missing data container. A container is considered missing if it does not exist with the exact name and location recorded in the VOB database. This definition implies missing version data (for a source pool) or a missing derived object (for a DO pool). During fix-mode processing, The checkvob command attempts to fix missing containers by scanning all storage pools for alternate containers from which to reconstruct the missing ones.
  • Debris. A container is considered debris if its pathname is not recorded in the VOB database. During –fix –debris processing, checkvob finds all debris in the source and DO pools. It checks various properties of an unreferenced container before moving it to the appropriate pool’s lost+found directory.

Whenever the VOB database and storage pools have different reference times, checkvob is likely to find both missing and unreferenced containers. For example, consider a container whose location has changed as a result of a rename operation on a pool: it stores the data that the database is trying to reference, but at the wrong location in the storage pool. checkvob reports a missing container and an unreferenced container, and can correct the problem in fix mode.