Cable connection guidelines

The following figures show the front-end director port configurations.

The following figures show how to connect the power distribution units to the power distribution panels. When connected as shown, the system operates normally if either AC inputs fails. In the following figures, redundancy is provided through separate PDUs. These figures assume the separate power distribution units are attached to independent PDUs.

This section provides basic cabling diagrams for connecting ENC (data and control) cables between the control chassis and the drive chassis in the block module, and between the controller and HNAS storage in the file module.

The following illustrations show how to connect the drive chassis to the controller.

By default, all storage systems installed in Hitachi Vantara racks are physically connected to each other. Two side panels are included to cover the sides of the outermost racks (see the following figure). To provide greater flexibility with the placement of the racks within a data center, there are multiple options for implementing separated rack configurations to meet the requirements of the customer. The following sections provide information about the available options and associated configuration rules. For more information about rack configuration and extended cabling options, contact a Hitachi Vantara representative.

The following figure shows a default rack placement.

Separated controller configuration

When designing a two controller VSP G1000 or VSP G1500 system, the default system configuration includes a primary and secondary controller chassis and each controller chassis is installed in a separate rack. This specific layout is referred to as a Twin Controller configuration and the racks are connected to each other.

For flexibility in placing the system in a data center, the rack containing the primary controller can be separated from the rack containing the secondary controller. The cable length options to connect the two controllers are 5 meters (standard length), 30 meters, and 100 meters. To avoid single points of failure, data and power cables can be connected to the controllers in a redundant configuration. Redundant configurations require that all cables to be the same length.

The following figure shows a two controller configuration with extended cabling between the racks containing the two controllers.

As shown in the configuration, in addition to the standard 5 meter connection, there are two optional features that can be ordered to enable the separation of the racks containing the two controllers in a dual controller storage system. Using the inter-controller connecting kit (DKC-F810I-MOD30) depends on whether the 30 or 100 meter cables are required.

The interconnect kit includes three different cable types of the required length (30 or 100 meter) and two Modcon packages (one package for each controller). Depending on whether both the basic and optional cache platform board features (cache path control adapter) are in installed, an addition of eight MFC optical cables may also be required along with the cables included with the interconnecting kit. The following cables are used for interconnecting various components in the primary controller to the equivalent component in the secondary controller:

• 8 x MFC or 16 x MFC Optical Cables (light blue)
• 2 x Modcon Optical Cables (green)
• 1 x LAN cable (light grey)

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 different cables used to separate the two controller racks. Where redundant routing is required, all of the CL1 interconnect cables along with one of the Modcon interconnect cables should be laid through one cable route and all of the CL2 interconnect cables, including the other Modcon cable, should be directed through an alternate cable route. The single LAN cable can be laid through either route direction. The only supported extended cable options are those specified by Hitachi. The intermixing of 30 meter and 100 meter cables in a single configuration is not permitted. Choosing the proper interconnection kit or cable length is determined by the longest cable route. When using extended cables between controllers, 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.

Separation of drive-only racks

A system can also be designed to separate a rack that includes a combination of controllers and drive chassis from multiple racks containing only drive chassis.

The following figure shows a single-controller configuration with extended cabling between rack R0 (containing the primary controller and two drive chassis) and R1 rack (containing two drive chassis). In addition, the extended cabling between drive chassis-only R1 rack and R2 rack. Extending the cabling between racks in a Twin Configuration is also supported.

To avoid I/O latency issues, the sum of the length of all cables (controller-to-drive chassis cable and drive chassis-to-drive chassis cables) cannot exceed 125 meters.

The following example shows a configuration of a controller controlling a maximum of six drive chassis.

There are three optional cable kits available to provide the separation of drive-only racks from either the control rack or adjacent drive-only rack.

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 specific configuration depends on various factors including the number of installed backend modules and racks being separated in the configuration.

The figure illustrates a single controller installed with both the basic and optional backend modules in a high performance, all-flash configuration using FMDs. The example uses the extended cable kit to separate the controller rack from the second drive rack. In this supported configuration, 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 configuration

A separated controller and drive-only rack configuration separates the rack with the controllers from a rack containing only drive chassis. This particular configuration combines both options described in the previous two examples.

The following figure shows a Twin controller configuration 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).

Although not shown in the following figure, the configuration can include an R2 rack directly connected to, or separated from the R1 rack. Similarly, the configuration can include an L2 rack directly connected to, or separated from the L1 rack. To avoid I/O latency issues, the sum of the length of all cables (controller-to-drive chassis cable and drive chassis-to-drive chassis cables) cannot exceed 125 meters.

Separated racks in a dual controller configuration

A dual controller configuration contains two controllers installed into a single rack. The dual controller configuration can include up to two flash memory drive chassis in the same rack and separate racks containing only drive chassis.

The following figure shows a dual controller configuration with extended SAS optical cables connecting between rack R0 (containing both primary and secondary controllers) and rack R1 (containing two drive chassis) and rack L0 (containing three drive chassis). To avoid any I/O latency issues the sum of the length of all cables (controller-to-drive chassis cable and drive chassis-to-drive chassis cable) cannot exceed 125 meters.

Additional guidelines

• You can implement extended cabling with a system installed in customer-supplied racks only if the racks meet HDS specifications and are approved by the HDS Customer Sales and Support (CSS) organization.
• The high temperature mode option can be implemented on VSP G1x00 systems using extended cabling.
• The minimum microcode requirements to support extended cabling includes:
  • VSP G1000: V02 (microcode 80-02-01-00/01), released in October 2014, must be installed to support the SAS optical cables
  • VSP G1500: SVOS 7.0 (microcode 80-05-01-00/00), released in October 2016, must be installed to support the SAS optical cables
  • To maintain proper functioning of storage system, continue to keep the storage system microcode level current to ensure code enhancements and fixes. If the storage system is using an earlier version of microcode, contact an authorized service provider for assistance with planning, ordering, and installing a more current microcode version.
• Consult a Hitachi Vantara representative for more information about system configurations and available extended cabling options.