RAID Planning
2-3
Optimization Mode
Figure 2 - 1 Optimization Setting
You should select an optimization scheme best suited to your
applications before configuring a RAID array. Once the
optimization mode is selected, it will be applied to all arrays
managed by the RAID controller.
Two options are available: Sequential I/Os and Random I/Os.
You may refer to the “Caching Parameters” section in Chapter
5 and Chapter 7 for the stripe size variables and its relations
with RAID levels.
Numerous controller parameters are tuned for each
optimization mode. Although stripe size can be adjusted on a
per logical drive basis, users are not encouraged to make a
change to the default values.
For example, smaller stripe sizes are ideal for I/Os that are
transaction-based and randomly accessed. However, using the
wrong stripe size can cause problems. When an array of the
4KB stripe size receives files of 128KB size, each drive will have
to write many more times to store data fragments of the size of
4KB.
Unlike the previous firmware versions, controller optimization
mode can be changed without changing the array stripe size.
The default values in optimization modes guarantee the
optimal performance for most applications. Consult Table 2-2
for all the controller parameters that are related to system
performance and fault- tolerance.
7. What RAID level?
Different RAID levels provide varying levels of performance
and fault tolerance.
