User manual

Fibre to SAS/SATA II RAID Subsystem

User Manual

takes longer. No Init (To Rescue Volume) is used to create a Volume Set without

initialization; normally used to recreate Volume Set configuration to recover data.

Stripe Size:

This parameter sets the size of the stripe written to each disk in a RAID 0, 1, 0+1, 5

or 6 Volume Set. You can set the stripe size to 4 KB, 8 KB, 16 KB, 32 KB, 64 KB, or

128 KB.

A larger stripe size produces better-read performance, especially if your computer does

mostly sequential reads. However, if you are sure that your computer does random

reads more often, select a small stripe size.

NOTE: Stripe Size in RAID level 3 can’t be modified.

Cache Mode:

The RAID subsystem supports two types of write caching: Write-Through and Write-Back.

Write-Through: data are both written to the cache and the disk(s) before the write

I/O is acknowledged as complete.

Write-Back: when data is written to cache, the I/O is acknowledged as complete,

and some time later, the cached data is written or flushed to the disk(s). This

provides better performance but requires a battery module support for the cache

memory, or a UPS for the subsystem.

Tagged Command Queuing:

When this option is enabled, it enhances the overall system performance under multi-

tasking operating systems by reordering tasks or requests in the command queue of

the RAID system. This function should normally remain enabled.

Fibre Channel/LUN Base/LUN:

Fibre Channel: Each RAID controller has two 4Gbps Fibre Host Channels (ports).

Select the Fibre port where

to map the LUN (Volume Set). Options are: 0, 1 and

0&1 Cluster. “0&1 Cluster” will make the LUN visible on both Fibre ports.

LUN Base: Th e base LUN number. Each LUN Base supports 8 LUNs.

LUN: Each Volume Set must be assigned a unique LUN ID number. A Fibre Port can

connect up to 128 devices (LUN ID: 0 to 127). Select the LUN ID for the

Volume Set.

NOTE: Refer to Appendix 1 for more information about mapping

LUNs/Volumes to Host Channel/Port in Dual Controller Mode.

Volumes To Be Created:

Use this option to create several Volume Sets with the same Volume Set attributes. Up

to 128 Volume Sets can be created.