Compaq Infortrend Optimization Mode and Stripe Size, Database and Transaction-based Applications

Database and Transaction-based Applications:

This kind of applications usually include SQL server, Oracle server, Informix, or other data base services. These applications keep the size of each transaction down to the minimum, so that I/Os can be rapidly processed. Due to its transaction-based nature, these applications do not read or write a bunch of data in a sequential order. Access to data occurs randomly. The transaction size usually ranges from 2K to 4K. Transaction performance is measured in “I/Os per second” or “IOPS.”

Video Recording/Playback and Imaging Applications:

This kind of applications usually includes video playback, video post-production editing, or other similar applications. These applications have the tendency to read or write large files from and into storage in a sequential order. The size of each I/O can be 128K, 256K, 512K, or up to 1MB. The efficiency of these applications is measured in “MB/Sec.”

When an array works with applications such as video or image oriented applications, the application reads/writes from the drive as large-block, sequential threads instead of small and randomly accessed files.

The controller optimization modes have read-ahead buffer and other R/W characteristics tuned to obtain the best performance for these two major application categories.

Optimization Mode and Stripe Size

Each controller optimization mode has preset values for the stripe size of arrays created in different RAID levels. If you want a different value for your array, you may change the controller optimization mode, reset the controller, and then go back to create the array. Once the array is created, stripe size can not be changed.

Using the default value should be sufficient for most applications.

	Opt. For Sequential I/O	Opt. for Random I/O
RAID0	128	32
RAID1	128	32
RAID3	16	4
RAID5	128	32

5-2 Infortrend