When you connect SAS cables between expansion enclosures, you must follow 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 Storwize® V7000 Gen3 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.
On Storwize V7000 Gen2 systems, the blue pull tab must be below the connector.
On Storwize V7000 Gen3 systems, to connect to the 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 attach the cables to the SAS ports.
No more than 10 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 10 expansion enclosures can be chained to SAS port 2 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 canister and a port on a right 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 enclosure in a chain must not have cables in port 2 of canister 1 and port 2 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.
Be aware of the following guidelines when you connect a control enclosure to
the SAS ports in 2U and 5U expansion enclosures.
Storwize V7000 systems support 4-port SAS
interface adapters. However, only ports 1 and 3 are used for SAS connections, as Figure 3 shows.
In general, the SAS interface adapter must be installed in PCIe slot 3 of the node canister.
No more than 10 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 3).
No more than 10 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 3).
No cable can be connected between a port on a left canister and a port on a right 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 2 of canister 1 or
port 2 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.
Note:Figure 3 shows an example configuration
of a control enclosure that is connected to two SAS chains;. Each chain consists of a 2U expansion
enclosure and a 5U high-density expansion enclosure. The order of the SAS ports on the 5U
high-density expansion enclosure differs from the SAS ports of a 2U expansion enclosure because the
canister is rotated.
