Multi-temperature data management guidelines
Your database data can be managed according to how frequently it is accessed. Termed multi-temperature database management, frequently accessed data (hot and warm data) is stored on fast storage devices and rarely accessed data (cold data) is stored on slower storage devices. Archived data is considered to be dormant and best stored on cold storage devices. For the IBM® PureData® System for Operational Analytics, hot and warm data is stored in the /db2fs file system and cold data is stored in the /bkpfs file system.
Multi-temperature data management gives you the ability to dynamically move infrequently accessed data (cold data) to a lower-cost storage device used for cold data and data archiving purposes. The aim is to keep frequently accessed data (hot and warm data) on fast, short access-time storage devices for only as long as the data remains hot and warm. Over time, hot and warm data, stored in the /db2fs file system set of table space containers, is accessed less frequently (becomes cold data). At that point, you can dynamically move the data to the cold data storage group in the /bkpfs file system on your data archiving storage device.
As a guideline for using the /bkpfs file system to store cold data, always retain enough storage space on /bkpfs for a single full database backup. This storage space on /bkpfs can be used in upgrade or expansion situations where an outage needs to be minimized, and a full backup to local disk is the fastest method of backing up data. Determine the space needed for a full backup image by noting the average and largest backup image size per database partition across the entire system. The remainder of the space can be used for storing cold data. Cold data is data that is no longer subject to updates, but can be subject to being read. It is suggested that you create storage groups to assist in this multi-temperature data management process. For the procedure to create a cold data storage group on the /bkpfs file system, see: Creating a core warehouse cold data storage group on the /bkpfs file system and moving cold data.
As the data warehouse grows, freeing up capacity in the /db2fs file system by moving cold data to the /bkpfs file system becomes more important.