Spread tablespaces across multiple disks

A table space is a logical unit of storage in a database. Generally speaking, spreading database table spaces across multiple disks improves performance.

A table space can be System Managed Space (SMS) or Database Managed Space (DMS). Each table space is a collection of containers. A container is a data storage location, such as a file, directory, or device. DB2® spreads data across containers so you can store data on multiple disks for greater speed and storage capacity.

Recommendations:

Before you create the database, make sure that you have multiple disks to split the table space containers. This approach helps to minimize I/O and improve overall performance.

Keep database containers and LOG files in different locations.

Split table spaces across multiple disks and keep them separate from the LOG file disk.

Create a user temporary table space and split it across multiple disks.

The LOGFILESIZ parameter defines the size of each primary and secondary log file. The default value of LOGFILSIZ is 1024, which might not be sufficient when deploying the Campaign application and populating the data into the tables. Consider increasing the LOGFILSIZ, LOGPRIMARY, and LOGSECOND based on the number of transactions that you anticipate.

Example 1: User database

During performance testing, disk utilization on the User Database machine pertaining to I/O is observed to go up to 100%. The database has a tablespace with containers spanned over two disks. After tuning and spreading containers over a total of 8 disks, in certain cases you may still see spikes but the average consumption is brought below 20% while running 5 concurrent complex flowcharts. User database tablespaces spread across multiple disks.

User database tablespaces spread across multiple disks.

Example 2: System database server

There is a possibility of Disk I/O contention on the IBM® Campaign System database server as well. Depending on your flowchart, a large amount of data may be written to the UA_CONTACTHISTORY table. For example, say you are running five multiple concurrent complex flowcharts, which are writing a large amount of data to UA_CONTACTHISTORY simultaneously. In this case, spreading database table spaces across multiple disks can improve performance. System tablespaces spread across multiple disks.

System tablespaces spread across multiple disks.

Generally speaking, spreading database table spaces across multiple disks improves performance. Whenever possible, create a database having tablespaces with containers spread across multiple disks at the time of the IBM® Campaign installation.