NonStop NS-Series Planning Guide (H06.04+)

Modular System Hardware
HP Integrity NonStop NS-Series Planning Guide—529567-005
5-24
Component Location and Identification
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.
Component Location and Identification
Topics discussed in this subsection are:
Terminology
Terms used in locating and describing components are:
Topic Page
Terminology
5-24
Rack and Offset Physical Location 5-25
NonStop Blade Element Group-Module-Slot Numbering 5-26
LSU Group-Module-Slot Numbering 5-27
Processor Switch Group-Module-Slot Numbering 5-28
IOAM Enclosure Group-Module-Slot Numbering 5-29
Fibre Channel Disk Module Group-Module-Slot Numbering 5-30
Term Definition (page 1 of 2)
Cabinet Computer system housing that includes a structure of external
panels, front and rear doors, rack, and dual PDUs.
Rack Structure inside the cabinet into which rackmountable
components are assembled.
Rack Offset The physical location of components installed in a rack,
measured in U values numbered 1 to 42, with 1U at the bottom
of the rack. A U is 1.75 inches (44 millimeters).
Group A subset of a system that contains one or more modules. A
group does not necessarily correspond to a single physical
object, such as an enclosure.
Module A subset of a group that is usually contained in an enclosure. A
module contains one or more slots. A module can consist of
components sharing a common interconnect, such as a
backplane, or it can be a logical grouping of components
performing a particular function.
Slot (or Position) A subset of a module that is the logical or physical location of a
component within that module.