SCSI Solutions White Paper - HP-UX

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HP-UX 11i v2, HP-UX is delivering self-healing software in the Ultra320 HBA driver which will
auto-detect signal integrity issues and downshift to Ultra160 speeds as needed.
Other features of the DS2120 include:
• 3.6TB of total storage per bus: up to three DS2120 enclosures can be daisy-chained
in single-initiator configurations (providing a total of up to 3.6TB of storage on a single
SCSI bus), and up to two DS2120’s can be daisy-chained in multi-initiator
configurations (providing up to 2.4 TB of storage per multi-initiator bus).
• Simple, low-cost, easy to install, configure, and support; a good solution for low-end
root/boot/swap/dump support and host-based HA solutions such as MirrorDisk/UX.
• Flexible: supports mixed disk capacities.
• Multi-initiator (dual host connect) capability
2.1.2 MSA30 Enclosures
The MSA30 products are Ultra320 SCSI 14-disk enclosures. They are intended for customers
that need external HA storage, enclosure management, full Ultra320 speeds, or SCSI RAID
Controller support. They provide redundant and hot-swappable fans and power supplies, hot-
swappable disk drives, and warm-swappable
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I/O modules and SCSI cables. The MSA30
enclosures come in a 3U package, as shown below in a top-front-right view, with the 14 disk
drive module units accessible in the front.
The MSA30 provides enclosure management support to monitor environmental conditions within
the enclosure and components, which can be accessed and controlled using EMS tools
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. These
enclosures are also fully supportive of Ultra320 speeds, drives, and HBAs.
The MSA30 comes in three flavors: the MSA30 SB (Single Bus), MSA30 DB (Dual Bus), and
MSA30 MI (Multi-Initiator), based on the type of I/O module in the back of the enclosure. The
SB I/O module provides a “full bus” mode of operation, in which all 14 drives are attached to
a single bus accessible via a single SCSI port. The DB and MI modules provide a “split bus”
mode of operation, splitting the enclosure into two separate SCSI buses, with 7 drive slots on
each bus. The DB I/O module contains two SCSI ports, one for each bus; the MI contains four
SCSI ports, two for each bus.
The MSA30 SB and DB only provide for the connection of one initiator per SCSI bus, and
therefore do not support multiple paths to a disk. If a path goes down and the data isn’t
mirrored or otherwise replicated on another bus (which in the DB case could be on the other
internal bus), the access to the data is lost. The MSA30 MI provides multi-initiator (shared bus)
support and the ability to build more complete HA solutions.
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Warm-swappable modules allow power to remain on but require all data transfers to the bus be stopped before removing or installing it.
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See http://docs.hp.com/en/diag.html. See also Section 6, “Storage Management”, below.
MSA30