Product specifications

Terminal Operation
4-3
The controller optimization modes have read-ahead buffer and other
Read/Write characteristics tuned to obtain the best performance for these
two major application categories.
4.2.2 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
optimization mode for a configured array, you must backup or move the
stored data and recreate the arrays following the steps below:
1. Stop host I/O access.
2. Move or backup all of your stored data in the subsystem.
3. Change the optimization mode.
4. Reset the subsystem.
5. Recreate the array(s). Once the array(s) are created, stripe size
cannot be changed.
Listed below are the default stripe sizes implemented with different
optimization modes and RAID levels. These values should be sufficient
for most applications.
Stripe Size:
Opt. for Sequential I/O
Stripe Size:
Opt. for Random I/O
RAID0
128KB 32KB
RAID1
128KB 32KB
RAID3
16KB 4KB
RAID5
128KB 32KB
RAID6
128KB 32KB
NRAID
128KB 32KB
Table 4-1: RAID Levels, Optimization Modes, and Stripe
Sizes
4.2.3 Optimization for Random or Sequential I/Os
Figure 4 – 2: Optimization for Random or Sequential I/Os