IBM DS3500 Introduction And Implementation Guide

Chapter 3. IBM System Storage DS3500 Storage System planning tasks 83
Draft Document for Review March 28, 2011 12:24 pm 7914DS3KPlanning_090710.fm
3.6.8 HP-UX IBM Subsystem Device Driver
IBM now offers a Subsystem Device Driver (SDD) for HP-UX. The SDD is only supported
through RPQ and provides the following functions:
򐂰 Enhanced data availability
򐂰 Dynamic input/output (I/O) load balancing across multiple paths
򐂰 Automatic path failover protection
򐂰 Concurrent download and installation of licensed machine code
See Figure 3-25 for information about the flow of an I/O operation.
Figure 3-25 SDD on HP-UX
SDD in combination with a DS3500 Storage System only HP-UX 11iv2 (11.23) is supported.
LVM is supported on HP-UX 11iv2 (11.23) and 11iv3 (11.31) as a multipathing driver.
More information about the architecture and installation of SDD can be found in the latest
Multipath Subsystem Device Driver User’s Guide, S7000303), or at the following link.
http://www.ibm.com/servers/storage/support/software/sdd
3.6.9 Linux: RHEL/SLES
In this section we discuss the Linux multipath options.
Redundant Disk Array Controller
The Redundant Disk Array Controller (RDAC), also known as Multi-Path Proxy (MPP), is the
preferred multipathing driver for Linux based operating systems such as Red Hat Enterprise
Linux (RHEL) or SUSE Linux Enterprise Server (SLES).
The current RDAC driver implementation performs the following tasks:
򐂰 Detects and claims the physical devices (LUNs) presented from the DS3500 Storage
Systems (
hides them) based on vendor/product ID strings and manages all of the paths to
the physical devices.
򐂰 Presents a single instance of each LUN to the rest of the Linux operating system
components.
򐂰 Manages all of the Plug and Play interactions.
򐂰 Provides I/O routing information.
򐂰 Identifies conditions requiring a request to be retried, failed, or failed over.
򐂰 Automatically fails over the LUNs to their alternate controller when detecting problems in
sending I/Os to the LUNs in their preferred controller, and fails back the LUNs to their
preferred controller when detecting the problems in the preferred path fixed.
򐂰 Handles miscellaneous functions, such as persistent reservation translation.
򐂰 Uses a round robin (load distribution or load balancing) model.

IBM DS3500 Specifications

General

Brand	IBM
Model	DS3500
Category	Storage
Language	English