Chapter 4: Subsystem Connection and Operation
EonStor U16U Subsystem Host Connection
4-3
Figure 4-2: Dual host Connection
4.2.3 Operation C onsiderations
NOTE: To create dual redundant data paths on the host side, it is necessary for third
party failover software to be installed on the host computer/s.
♦
Redundant Host Paths - In the two topologies shown above (see Figure 4-1 and
Figure 4-2), if either of the host channel fails, the alternate host channel will continue
to transmit data between the host computer/s and the ES U16U. That is, if CH0 fails,
all traffic will be transmitted through CH1 and vice versa.
♦
Redundant Host Computers – In Figure 4-2 if either of the host computers fail data is
still accessible through the second host computer. That is, if the host computer
connected to CH1 fails, the data can still flow through the host computer connected
to CH0 and vice versa. If in Figure 4-1 the host computer fails, data that is stored on
the ES U16U hard drives will not be accessible until host computer functionality is
restored.
4.2.4 Expansion
Two SCSI ports on the six channel models (ES U16UG4010-62-0030 and ES
U16UG4010-65-0030) can be used for capacity expansion to cascade a RAID system
with a JBOD. Connect the SCSI ports on the controller box’s face plate (marked as CH4
and CH5) to ports on a JBOD. No termination setting is necessary, and there is no
limitation as to which expansion port should be connected with which port on a JBOD.
To be able to monitor the status of different JBOD components it is necessary to use a
JBOD that can be connected to the I
2
C port on the ES U16U subsystem. See
Figure 4-3
.
