EonStor DS S48 Series Hardware Manual
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. The active IDs are in black while the
passive IDs are in blue. 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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