Hitachi G1500 - Page 116

There are three optional cable kits available to provide the separation of drive-only racks
fr
om either the contr
ol r
ack or adjacent drive-only r
ack.
Each kit contains eight optical cables in either 5, 30, or 100 meter lengths and provides
enough cables to support the SAS paths from one backend module feature or pair of
disk boards. The number of drive rack interconnection kits required for a specic
conguration depends on various factors including the number of installed backend
modules and racks being separated in the conguration.
The gure illustrates a single controller installed with both the basic and optional
backend modules in a high performance, all-ash conguration using FMDs. The
example uses the extended cable kit to separate the controller rack from the second
drive rack. In this supported conguration, only the cables in the controller interconnect
kit are provided by Hitachi.
When a customer adopts diverse routing of host cables within their data center for
resiliency and redundancy reasons, it is possible to follow the same approach for the
cables that are used to separate the two racks. Where redundant routing is required, all
of the cables extending the SAS paths from any backend modules in CL1 should be laid
through one cable route and all cables extending the SAS paths from any backend
modules in CL2 should be directed through an alternate route. The cables connecting
any two racks must be the same length so choosing the proper cable kit is determined by
the longest cable route between the two racks. When using extended cables between
racks, Hitachi recommends taking precautionary steps such as routing the cables
through the cable trays in order to protect the cables from any accidental physical
damage.
Separated controller and drive-only rack conguration
A separated controller and drive-only rack conguration separates the rack with the
controllers from a rack containing only drive chassis. This particular conguration
combines both options described in the previous two examples.
The following gure shows a Twin controller conguration with extended SAS optical
cabling between R0 rack (containing the primary controller) and R1 rack (containing two
drive chassis), as well as between L0 rack (containing the secondary controller) and L1
rack (containing two drive chassis).
Extended cable connections
Chapter 5: Cable connection guidelines
Hitachi Virtual Storage Platform G1000, G1500, and VSP F1500 Hardware Guide 116