NonStop NS1000 Planning Guide (H06.07+)

Modular System Hardware
HP Integrity NonStop NS1000 Planning Guide—542527-003
5-18
Enterprise Storage System (Optional)
High availability and a fault-tolerant configuration for one IOAM enclosure and pairs of
FCSAs are similar to the configurations required for Fibre Channel disk drives, as
explained in IOAM Enclosure and Disk Storage Considerations on page 6-9.
Cables and switches vary, depending on whether the connection is direct, switched, or
a combination:
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.
Refer to the documentation that accompanies the ESS.
Connection LC-LC Cables Fibre Channel Switches
Direct-connect 2 per FCSA 0
Switched 4 per FCSA 1 or more
Combination of
direct and switched
2 per FCSA for each direct connection
4 per FCSA for each switched connection
1
VST068.vsd
Fibre
Channel
Switch
ESS
IOA M
Enclosure
Fibre Channel
Switch
IOA M
Enclosure
FCSA
FCSA