Monitoring Fragmentation Use

The database administrator might find the following aspects of fragmentation useful to monitor:

• Data distribution over fragments
• I/O request balancing over fragments
• The status of chunks that contain fragments

The administrator can monitor the distribution of data over table fragments. If the goal of fragmentation is improved single-user response time, it is important for data to be distributed evenly over the fragments. To monitor fragmentation disk use, you must monitor database server tblspaces because the unit of disk storage for a fragment is a tblspace. (For information on how to monitor the data distribution for a fragmented table, see Monitoring Tblspaces and Extents.)

The administrator must monitor I/O request queues for data that is contained in fragments. When I/O queues become unbalanced, the administrator should work with the DBA to tune the fragmentation strategy. (For a discussion of how to monitor chunk use, including the I/O queues for each chunk, see Monitoring Chunks.)

The administrator must monitor fragments for availability and take appropriate steps when a dbspace that contains one or more fragments fails. For how to determine if a chunk is down, see Monitoring Chunks.