IBM Tivoli Monitoring > Version 6.3 Fix Pack 2 > Installation Guides > Installation Guide > Performance tuning > Tivoli Data Warehouse > Relational database design and performance tuning for DB2 Database servers > Database design details > Table spaces
IBM Tivoli Monitoring, Version 6.3 Fix Pack 2
Performance and table space types
DMS table spaces usually perform better than SMS table spaces because they are pre-allocated and do not use up time extending files when new rows are added. DMS table spaces can be either raw devices or file system files. DMS table spaces in raw device containers provide the best performance because double buffering does not occur. Double buffering, which occurs when data is buffered first at the database manager level and subsequently at the file system level, might be an additional cost for file containers or SMS table spaces.
If you use SMS table spaces, consider using the db2empfa command on your database. The db2empfa command, which runs the Enable Multipage File Allocation tool, runs multipage file allocation for a database. With multipage file allocation enabled for SMS table spaces, disk space is allocated one extent rather than one page at a time, improving INSERT throughput. In version 8 of DB2, this parameter is turned on by default.
If you are using a RAID device, create the table space with a single container for the entire array. When a database is created in DB2, a default table space called USERSPACE1 is created, and by default, Tivoli Monitoring uses this table space when creating its tables in the DB2 database. You can create a new default table space in DB2 by creating a table space with the name IBMDEFAULTGROUP. If a table space with that name, and a sufficient page size, exists when a table is created without the IN table space clause, it is used. You can create the table space in a different location, for example, a RAID array. You could also create it as a DMS table space if you prefer, as in the following example:
CREATE REGULAR TABLESPACE IBMDEFAULTGROUP IN DATABASE PARTITION GROUP IBMDEFAULTGROUP PAGESIZE 4096 MANAGED BY SYSTEM USING ('E:\DB2\NODE0000\SQL00001\IBMDEFAULTGROUP') EXTENTSIZE 32 PREFETCHSIZE AUTOMATIC BUFFERPOOL IBMDEFAULTBP OVERHEAD 12.670000 TRANSFERRATE 0.180000 DROPPED TABLE RECOVERY ON;
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Table spaces