External RAID Controller & Subsystem Operation Manual

Infortrend
5-2
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