XADM: Orphaned LV Errors When Running ESEUTIL Consistency Checker (185271)

SYMPTOMS

When you are running ESEUTIL in integrity mode (ESEUTIL /G <dbname> /X), the output contains information similar to the following:

   ERROR: orphaned LV (lid 62322, size 80682). Non-corrupting error
   ERROR: node [514410:0]: leaf node check failed

CAUSE

Long values (LVs) are created by the Exchange database engine when a column is too large to store with the rest of the record. Large columns are broken into separate groupings, which are the long values. Long values are stored in a separate binary tree (B-Tree), and each LV is given a table-wide unique identifier (the LID, or long value ID).

To save database space, the Exchange database engine allows multiple records to share the same long value (similar to, but not really related to the information store's concept of single-instance storage for messages). To do this, a reference count (refcount) is attached to each long value. When the refcount reaches zero, the long value is deleted.

In a rare case where the Exchange database crashes after deferencing a long value but before expunging it from the database, the long value is "orphaned." Its refcount will be zero, but it will never be removed. Orphaned long values are invisible to anyone using the database because they are logically deleted, but they still take up space because they have not been physically removed.

WORKAROUND

This is a harmless error. The orphaned LVs take up space but do not interfere with the operation of the database. You can remove the orphaned LVs and reclaim the space using defragmentation.

However, it is recommended that you perform defragmentation only if the space occupied by orphaned LVs is a significant percentage of the total database space. This value can be determined by looking at the size reported in the error message.

To remove orphaned long values and reclaim the space, perform the following steps:

Stop either the directory or the information store service, depending on which database the errors were reported against.
Run ESEUTIL /d /ds or ESEUTIL /d /ispriv or ESEUTIL /d /ispub to defragment the database.
After ESEUTIL completes with no errors, restart the Exchange services.
Perform a full online backup of the information store databases.

MORE INFORMATION

In Exchange 5.5, ESEUTIL run in integrity or repair mode (ESEUTIL /g or ESEUTIL /p) will only detect the orphaned LVs. To remove the orphaned long values, you must run ESEUTIL and defragment (ESEUTIL /d) the affected database.