Communications - Adaptec RAIDStation RS/7F User Manual

Environmental Monitoring

Communications

The RAIDstation7 Fibre Channel Storage Array uses the SES feature of Fibre
Channel disk drives to communicate with the VEM. The SES communication is
carried out through disk drives 4 or 5 as shown in Figure 4-3.
Figure 4-3.SES communication through disk drives 4 or 5
The host system (via the Adaptec controller, with SES capability) may request
information from the VEM through either Fibre Channel disk drive 4 or 5. The
host system will send commands through the Fibre Channel cable to either disk
drive 4 or 5 (which ever is free to communicate). The disk drive will then inter-
pret the command and determine if it needs to obtain information from the VEM
and return it to the host, or obtain more data from the host, and forward it to the
VEM.
By having two Fibre Channel disk drives configured for SES communication
there is full redundancy. If the disk drive 4 is failed or missing then the VEM will
communicate with the host system through the disk drive 5. Likewise, if the disk
drive 5 is failed or missing then the VEM will communicate with the host system
through the disk drive 4. When both disk drives 4 and 5 are installed and operat-
ing correctly the host system will use the first available disk drive (4 or 5) for
communication.
CAUTION: To use the VEM in the RAIDstation7 Fibre Channel Storage
Array, Fibre Channel disk drives 4 or 5 must be installed.
4-4
Disk Drive 1
Disk Drive 2
Disk Drive 3
Disk Drive 4
Disk Drive 5
Disk Drive 6
Disk Drive 7
Power Supply
Power Supply
SES
Communication