Veritas InfoScale™ 8.0.2 Storage and Availability Management for Oracle Databases - AIX, Linux, Solaris

Extent balancing in a database environment using SmartTier for Oracle

To obtain better performance in a database environment, you would normally use a volume striped over several disks. As the amount of data stored in the file system increases over time, additional space in the form of new disks must be added.

To increase space, you could perform a volume relayout using the command. However, changing a large volume, for example, from a four-way striped volume to six-way striped volume involves moving old block information into temporary space and writing those blocks from the temporary space to a new volume, which would require an extended amount of time. To solve this problem, SFDB tools provide the Extent Balanced File System or EBFS .

An Extent Balanced File System is created on a multi-volume file system where individual volumes are not striped over individual disks. For data-availability, these individual volumes can be mirrored. The file system on the EBFS has a special placement policy called a balance policy. When the balance policy is applied, all the files are divided invxrelayoutto small "chunks" and the chunks are laid out on volumes so that adjacent chunks are on different volumes. The default chunk size is 1MB and can be modified. Since every file contains chunks on all available volumes, it is important that individual volumes that make up the EBFS and volume set be of same size and same access properties.

Setting up the file system in this way provides the same benefit as striping your volumes.