Specifications

SCSI to SATA RAID Subsystem | Administrator’s Manual LCD Keypad Operation | en 49

Bosch Security Systems F.01U.027.802 | V1 | 2006.11

5.2.2 Optimization Mode and Stripe Size

Each controller optimization mode has preset values for the stripe size of arrays created in dif-

ferent RAID levels. If you want a different setting for a subsystem with configured arrays, you

have to backup or move the stored data and re-create the arrays:

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 controller.

5. Re-create 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:

5.2.3 Optimization for Random or Sequential I/Os

5.2.4 Write-back/Write-through Cache Enable/Disable

As one of the submenus in "Caching Parameters," this option controls the cached write func-

tion. Press ENT to enable or disable “Write-back Cache.” Press ENT for two seconds to con-

firm. The current status will be displayed on the LCD.

The Write-through mode is safer if your subsystem is not managed by a controller pair and

there is no battery backup.

Opt. For Sequential I/O Opt. for Random I/O

RAID0 128KB 32KB

RAID1 128KB 32KB

RAID3 16KB 4KB

RAID5 128KB 32KB

NRAID 128KB 32KB

Table 5.1 RAID Level, Optimization Modes, and Stripe Sizes

NOTICE!

The original 512GB threshold on array optimization mode has been canceled. If the size of an

array is larger than 16TB, only the optimization for sequential I/O can be applied. Logical

drives of this size may not be practical; therefore, there is actually no limitation on the optimi-

zation mode and array capacity.