iSCSI-to-SATA II RAID Subsystem
14
User Manual
1.5 Volume Relationship Diagram
This diagram shows how the volume structure of the iSCSI RAID subsystem is
designed. It describes the relationship of RAID components. One RG (RAID group)
consists of a set of VDs (Virtual disk) and owns one RAID level attribute. Each RG can
be divided into several VDs. The VDs in one RG share the same RAID level, but may
have different volume capacity. Each VD will be associated with the Volume Cache
(portion of cache memory) to execute the data transaction. LUN (Logical Unit Number)
is a unique identifier assigned to every VD, and users access the LUN through SCSI
commands.
RG
PD 2
PD 3
DS
PD 1
VD 1
VD 2
VD 3
RAM (cache memory)
Volume
Cache
System
Cache
+
LUN 1
LUN 2
LUN 3
+
+