Product specifications

Infortrend
4-2
4.2 Caching Parameters
4.2.1 Optimization Modes
Mass storage applications can be roughly divided into two categories—
database and video/imaging—according to their read/write characteristics.
To optimize system operation, there are two embedded optimization modes
with system behaviors pre-adjusted to different read/write parameters:
“Optimization for Random I/O” and the “Optimization for Sequential I/O.”
Limitations
The following are the limitations on the use of optimization modes.
1. The system default is Optimization for Sequential I/O.
2. You can select the stripe size of each array (logical drive) during the
initial configuration. However, changing stripe size is only
recommended for experienced engineers who have tested the effects of
tuning stripe sizes for different applications.
3. The array stripe size can only be changed during the initial
configuration process.
4. Carefully consider the outcome before choosing an optimization mode.
Once the controller optimization mode is applied, access to different
arrays in a RAID system will follow the same optimized pattern. You
can only change the optimization mode after recreating the arrays.
Database and Transaction-based Applications
These kinds of applications usually include SQL server, Oracle server,
Informix, or other database services that keep the size of each transaction
down to a minimum, so that I/Os can be rapidly processed. Due to their
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
These kinds of applications usually include video playback, video post-
production editing, or applications of a similar nature that tend to read or
write large files to and from 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 per second (MBps).
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.