IBM Enterprise Storage Server 2105 E10, Introduction And Planning Manual

Page: 36 / 156

Introducing the IBM Subsystem Device Driver
The IBM Subsystem Device Driver resides in the host server with the native disk
device driver for the ESS. It uses redundant connections between the host server
and disk storage in an ESS to provide enhanced performance and data availability.
Figure 7 on page 13 is an example of the type of configuration that IBM Subsystem
Device Driver supports. These connections comprise many different components
through which data flows during input and output processes. Redundancy and the
ability to switch between these components provides many different paths for the
data to travel. In the event of failure in one input-output path, it automatically
switches to another input-output path. This automatic switching in the event of
failure is called
failover .
S008943N
1
2
1
2
Legend
«1¬
is the host system.
«2¬
is the ESS.
Figure 6. Arbitrated loop topology
12
ESS Introduction and Planning