User`s manual

SAS / SATA II NAS System
User’s Manual
61
Cache Mode:
The RAID subsystem supports Write-Through Cache and Write-Back Cache.
Write-Through: the RAID controller acknowledges data has been received when it
reaches the disk drives.
Write-Back: the RAID controller acknowledges data has been received when it
reaches the controller’s cache memory. This provides better performance but requires
a battery module support for the cache memory, or a UPS where the system can be
connected.
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.
SAS Port/LUN Base/LUN:
SAS Port: There are two 3Gbps SAS Host Channels in the RAID
subsystem. Select
the SAS 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 SAS ports.
LUN Base: The base LUN number. Each LUN Base supports 8 LUNs.
LUN: Each Volume Set must be assigned a unique LUN ID number. A SAS Port can
connect up to 128 devices (LUN ID: 0 to 127). Select the LUN ID for the
Volume Set.
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.