Directory locations and index storage for Net Search Extender

The disk space you need for a Net Search Extender index depends on the amount and type of data you want to index.

As a guideline for indexing single-byte documents, reserve disk space of about 0.7 times the size of the documents you want to index. For double-byte documents, reserve the same disk space as the total size of the documents you want to index. The total size might have to include data stored outside the active database that is retrieved through user-defined functions.

The amount of space needed for the temporary files in the work directory is 1.0 to 4.0 times the amount of space needed for the final index file in the index directory. The default index directory is a subdirectory of the Db2® instance directory which is usually located in the /home partition of the system (for Linux® and UNIX operating systems) and on the C: drive (for Windows operating systems). The default index might have size limitations as well. See Views for database-level information for more details.

If you have several large indexes, store them on separate disk devices, especially if you have concurrent access to the indexes during index update or search.

For each index, the corresponding index and work directory should reside on the same file system or drive. If you are not using the default location, then care should be taken during the create index command to specify both the index and work directory locations, such that they are on the same file system. Specifying only the index directory in the command leads to the work directory getting created in the default path (which in most cases may not be on the same file system) and vice versa.

For a partitioned database, a text index still uses a single file system on a physical machine to place the index. For large databases, place the index and work directories on a file system that is on a Redundant Array of Independent Disks (RAID) device. This minimizes the possibility of hitting an I/O bottleneck while using the text indexes.

For creating, updating, and deleting Net Search Extender indexes, use the command line interface.