NonStop S-Series Planning and Configuration Guide (G06.29+)

The Planning and Configuration Process
HP NonStop S-Series Planning and Configuration Guide—523303-021
9-10
Enclosure Interleaving for Storage Devices
Recommendations
These recommendations are not required, except where they conform to the preceding
limitations.
For all disk, tape, and Open SCSI Devices
•
Configure the -P and -B paths to a device through different adapters, one on the X
fabric and the other on the Y fabric.
•
Configure a device to use the two processors that are in the same topology branch
as the adapter used for the -P path to the device. These processors are chosen by
default if no processors are specified in an SCF ADD command.
For All Disk Drives
•
Within a topology branch, interleave the adapters for mirrored disk volumes across
enclosures in a circular pattern. For example, in a topology branch consisting of
enclosures 04, 41, and 42, arrange the primary and mirror drives as follows.
For All Open SCSI Devices
•
Configure the -P and -B paths to an Open SCSI device to use adapters in the
same enclosure.
For All External Disk Drives
•
Configure the primary and mirror halves of a mirrored external disk volume to have
the same device ID in two different external disk modules.
•
Configure all paths to an external disk drive to use SACs with the same SAC
number on different 6760 adapters.
•
Configure the -P and -B paths to an external disk to use 6760 adapters in the same
enclosure. You can also configure the -P and -M paths to different enclosures, but
that is not necessary for fault tolerance, because the primary drive and mirror drive
are configured in different enclosures.
•
Configure the -M and -MB paths to an external disk to use 6760 adapters in the
same enclosure.
Note. This subsection does not apply to the Fibre Channel disk drives that reside in modular
disk drive enclosures (DDEs). $SYSTEM cannot exist on these disk drives. For more
information about the DDE, refer to the Modular I/O Installation and Configuration Guide.
Primary in Enclosure Mirror in Enclosure
04 41
41 42
42 04