If the database server determines that a dbspace is unavailable as the result of a disk failure, queries directed to that dbspace fail by default. You can specify the database server behavior in such cases, as described in Specifying Spaces that Can Be Skipped if Not Available.
Many DSS queries require statistical data instead of exact data. When you specify dbspaces that can be skipped, consider the degree of precision that your queries require and how the data in the skipped dbspaces might affect query results.