NonStop NS16000 Series Planning Guide (H06.11+)

NOTE: The NonStop system console must be configured with some ports open. For more
information, see the NonStop System Console Installer Guide.
For more information on the system console, refer to “System Console” (page 147).
Enterprise Storage System
An Enterprise Storage System (ESS) is a collection of magnetic disks, their controllers, and a disk
cache in one or more standalone cabinets. ESS connects to the Integrity NonStop NS16000 series
systems either directly via FCSAs in IOAM enclosures (direct connect) or through separate storage
area network (SAN) using a Fibre Channel SAN switch (switched connect). For more information
about these connection types, see the Fibre Channel ServerNet Adapter Installation and Support
Guide.
High availability and fault-tolerant configurations for one or two IOAM enclosures and pairs of
FCSAs are similar to the configurations required for Fibre Channel disk drives, as explained in
“IOAM Enclosure and Disk Storage Considerations” (page 92).
Cables and switches vary, depending on whether the connection is direct, switched, or a
combination:
Fibre Channel SwitchesLC-LC CablesConnection
02 per FCSADirect connect
1 or more4 per FCSASwitched
12 per FCSA for each direct
connection4 per FCSA for each
switched connection
Combination of direct and switched
This illustration shows an example of connections between two IOAM enclosures and an ESS via
the separate Fibre Channel switch:
For fault tolerance, the primary and backup paths to an ESS logical device (LDEV) must go through
different Fibre Channel switches.
Some storage area procedures, such as reconfiguration, can cause the affected switches to pause.
If the pause is long enough, I/O failure occurs on all paths connected to that switch. If both the
primary and the backup paths are connected to the same switch, the LDEV goes down.
Enterprise Storage System 133