Infortrend S12 Series Hardware Manual page 82

EonStor / EonStor DS S12/S16/S24 Series
Channel link bypass is provided on external FC switches. Each of the application
servers shown in the diagram is equipped with two HBAs with FC links via two FC
switches to the SFP ports on individual RAID controllers.
You can refer to the ID tags on the host links to see the related logical volume
mapping and cable links routing paths. Through the cable links illustrated above, the
configuration can withstand a failure of a single component, e.g., RAID controller,
HBA, cable, or FC switch.
Each logical partition is redundantly mapped to multiple host channel IDs in an AAPP
(Active-Active-Passive-Passive) configuration. Logical volumes are managed either
by the controller A or by the controller B. The Passive IDs will only become functional
when a single controller fails in the system. The EonPath driver is a must on the
application servers. The driver communicates with system firmware and performs
load balance and automated distribution of I/Os across preferred paths (Active IDs
on data paths). TPGS (Target Port Group Service) is supported so that I/Os are
routed to the preferred paths.
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