When you connect SAS cables between enclosures, you must follow a list of guidelines to
ensure that your configuration is valid.
Orienting the connector
When you insert SAS cables, make sure the connector (Figure 1) is oriented correctly.
The orientation of the connector must match the orientation of the port before you
push the connector into the port. The cable connector and socket are keyed, and it is important that
you have proper alignment of the keys when the cable is
inserted.
Note:On FlashSystem 7200 systems, node canister 1 is
inverted from node canister 2. Because the orientations of the ports differ, you must ensure
that the orientation of the SAS cables is also correct for each canister.
For ports in the upper canister (canister 1), the blue pull tab must be above the
connector. For ports in the lower canister (canister 2), the blue pull tab must be below the
connector.
Insert the connector gently until it clicks into place. If you feel resistance, the
connector is probably oriented the wrong way. Do not force it.
When inserted correctly, the connector can be removed only by pulling the tab.
When both ends of a SAS cable are inserted correctly, the green link LEDs next to
the connected SAS ports are lit.
Figure 1. SAS cable connectors
Guidelines
Be aware of the following guidelines when you connect a FlashSystem 7200 control enclosure to the SAS
ports in 2U and 5U expansion enclosures.
The FlashSystem 7200 system supports 4-port SAS
interface adapters. However, only ports 1 and 3 are used for SAS connections, as Figure 2 shows.
The SAS interface adapter must already be installed in PCIe
slot 3 of each node canister when you unpack the control enclosure.
No more than ten 2U expansion enclosures can be chained to SAS port 1 of a node canister. The
expansion enclosures in this chain must be installed below the control enclosure, as shown in Figure 2.
No more than ten 2U expansion enclosures can be chained to
SAS port 3 of a node canister. The expansion enclosures in this chain must be installed above the
control enclosure, as shown in Figure 2.
No cable can be connected between a port on a left expansion canister and a port on a right
expansion canister.
A cable must not be connected between ports in the same enclosure.
A connected port on the node canister must connect to a single port on an expansion canister.
Cables that split the connector out into separate physical connections are not supported.
Attach cables serially between enclosures; do not skip an enclosure.
The last expansion enclosure in a chain must not have cables in port 1 of canister 1 or port 1
of canister 2.
Ensure that cables are installed in an orderly way to reduce the risk
of cable damage when replaceable units are removed or inserted.
