EMC Symmetrix DMX-3 User Manual

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EMC Symmetrix DMX-3 Product Guide
Symmetrix DMX-3 Input/Output Operations
◆ Using the prefetch algorithm, the disk director dynamically
detects sequential data access patterns to the disk drives. The
directors improve the hit ratio of these accesses by promoting
blocks from the disk drives to global memory slots before that
data has been requested. The prefetch algorithm is designed to
minimize seek and latency on the disks, and to provide good
response times.
◆ The disk director manages access to the disk drives. When a read
miss occurs, the disk director also stages tracks into global
memory. It also performs a background operation that destages
written-to blocks to disk.
Prefetch algorithm Symmetrix systems continually monitor I/O activity and look for
access patterns. When the second sequential I/O to a track occurs, the
sequential prefetch process is invoked and the next track of data is
read into global memory. The intent of this process is to avoid a read
miss. When the host processor returns to a random I/O pattern, the
Symmetrix system discontinues the sequential process.
The intelligent, adaptive prefetch algorithm reduces response time
and improves the utilization of the disks. The prefetch algorithm
maintains, per each logical volume, an array of statistics and
parameters based on the latest sequential patterns observed on the
logical volume. Prefetch dynamically adjusts, based on workload
demand across all resources in the back end of the Symmetrix system.
This algorithm also ensures that global memory resources are never
overly consumed in order to maintain optimal performance.
Enginuity uses an intelligent algorithm attuned to “real-life”
workloads and dynamic usage patterns which will detect sequences
quickly, but prefetch only when the probability of increasing global
memory hits is high. It will place data in memory on time and
without interfering with other system activities. The prefetch to
memory resulting in global memory hits dramatically improves
response to a host request by as much as a factor of 10. It also
optimizes back-end utilization by transferring large portions of data
in each instance, minimizing seek and latency delays associated with
I/O operations directly from disk.
By incorporating intelligent prefetch algorithms, Enginuity
prefetches all the data that is needed—and only the needed
data—and does it on time, without affecting the response time of
other I/O events. Enginuity’s algorithms are the most sophisticated
and advanced in the industry and are optimized for what you need
next. They can adjust for real-world situations and intelligently
choose the method that works best for a given situation.

EMC Symmetrix DMX-3 Specifications

General

Model	Symmetrix DMX-3
RAID Levels Supported	RAID 1, RAID 5, RAID 6, RAID 10
Form Factor	Rack-mountable
Installed Devices / Modules Qty	Varies by configuration
Drive Types Supported	Fibre Channel
Connectivity	Fibre Channel
Host Interface	Fibre Channel
Data Transfer Rate	4 Gbps Fibre Channel
Operating System Support	Linux, Windows
Data Replication	SRDF

Summary

Introducing the Symmetrix DMX-3

Symmetrix DMX-3

Overview of the Symmetrix DMX-3 system, its architecture, and performance capabilities.

Symmetrix Platform and Enginuity Operating Environment

Details on the Symmetrix DMX hardware architecture and the Enginuity operating environment.

Storage Capacities and Global Memory Requirements

Describes storage capacities for DMX-3 systems and factors affecting disk storage capacity.

Performance Features

Highlights Symmetrix DMX-3 features that enhance performance and increase throughput.

Availability and Integrity Features

Details enhancements for reliability, availability, and serviceability in Symmetrix DMX-3 systems.

Serviceability Features

Explains the integrated service processor and nondisruptive component replacement.

Supported Software Applications

Overview of software offerings like Tiered Storage Optimization and Storage Management.

Hardware Options

Describes available hardware options for the DMX-3 systems, such as the DMX-3 Silencer.

Symmetrix DMX-3 Hardware

Major Components

Describes the system bay and storage bays, detailing their internal components and layout.

Symmetrix DMX-3 Architecture

Details the Direct Matrix Architecture (DMX) supporting point-to-point connections within the system.

DMX-3 Slot Configuration

Explains the midplane slot layout for global memory directors and channel/disk directors.

Symmetrix Channel Connectivity and Host Integration

Outlines emulations and hosts supported through Fibre Channel, iSCSI, ESCON, FICON interfaces.

Fibre Channel Disk Subsystem

Details the storage bays, disk drives, link control cards, and power/cooling modules.

Channel, Disk, and Global Memory Directors

Describes the functions of channel, disk, and global memory directors in managing storage.

Symmetrix DMX-3 Power Subsystems

Explains the 2N power architecture, power zones, and system bay power components.

DMX-3 Communications and Environmental Control

Details the Environmental Control Module (ECM) and Communication Control Module (CCM) functions.

Channel Attachments

Describes connection types to ESCON, FICON, and Fibre Channels, including FICON configurations.

Symmetrix DMX-3 Input/Output Operations

Symmetrix DMX-3 Operation

Explains how intelligent global memory configurations enable electronic memory speed data transfers.

Elements of a Symmetrix I/O Operation

Details I/O response time, breaking it down into queuing, pend, connect, and disconnect times.

I/O Performance Enhancements

Describes techniques used to enhance performance, such as split director functions and global memory speed.

Performance and Optimization

Overview

Discusses real-world workloads and how Symmetrix Enginuity algorithms optimize response time.

Global Memory Performance Features

Details features like ASICs, buffering, arbitration, and striping for high performance.

Symmetrix File System Performance Features

Explains the benefits of the Symmetrix File System (SFS) for performance algorithms.

Multiple Channel Directors

Covers channel speeds, cable lengths for various director types like Fibre Channels and ESCON.

Open Systems Hypervolumes

Describes the Hypervolume Extension feature for open systems units, including logical volume mapping.

Mainframe Systems Hypervolumes

Explains Hypervolume Extension for mainframe volumes, including split-volume capability.

Tiered Storage Optimization

Details software offerings like Symmetrix Priority Controls and Dynamic Cache Partitioning.

Optimizing Symmetrix System Performance

Provides guidelines for open system devices and planning for system upgrades.

Virtual LUN Technology

Discusses transparent data mobility between storage tiers via migration and relocation.

Virtual Provisioning

Explains how Virtual Provisioning grants large storage space while consuming only used space.

Multiport Volume Access for Open Systems Environments

Describes presenting logical volumes through multiple Fibre Channel channels for host failover.

Software Options Overview

Introduces EMC ControlCenter, Symmetrix Optimizer, TimeFinder, and Solutions Enabler.

Data Integrity, Availability, and Protection

Overview

Discusses features and options for high system and data availability.

Reliability and Availability Features

Details high-reliability components, redundancy in memory, channels, and power subsystems.

Maintaining Data Integrity

Explains error checking, correction, and remote support for data integrity.

DMX-3 Security Features

Covers IPsec, Service Credentials, Audit Logs, RSA enVision, and Data Erasure.

Data Protection Guidelines

Outlines options like Mirroring (RAID 1), RAID 1/0, RAID 10, RAID 5, RAID 6, SRDF, and Sparing.

Disk Mirroring (RAID 1) Concepts

Explains RAID 1 mirroring, its advantages, write/read operations, and error recovery.

Symmetrix RAID 1/0 for Open Systems

Describes RAID 1/0 as a stripe of mirrored pairs for open systems environments.

Symmetrix RAID 10 for Mainframe Systems

Details RAID 10 implementation for mainframe environments using mirrored pairs and striping.

Symmetrix DMX RAID 5

Explains RAID 5 (3+1) and (7+1) features, attributes, and modes of operation.

Symmetrix DMX RAID 6

Describes RAID 6 (6+2) and (14+2) features, attributes, and the Even-Odd algorithm.

Sparing in Symmetrix Systems

Covers permanent and dynamic sparing functionality and configuration rules.

SRDF Family of Products

Details SRDF replication solutions for business continuance and disaster recovery.

Mainframe Features and Support

Introduction

Overview of Symmetrix mainframe storage solutions and Enginuity operating environment.

Supported Mainframe Features

Lists IBM/PCM functions and features supported by Symmetrix DMX systems connected to mainframes.

Error Reporting and Recovery

Discusses error types, handling techniques, and error recovery summaries for mainframe connections.

Sense Byte Information

Explains console error messages, unit status bits, and channel status bits.

Appendix A: Symmetrix DMX-3 Specifications

Storage Control

Details emulation types, channel speeds, and storage capacities for DMX-3 systems.

Physical Data

Provides physical specifications, including dimensions, clearances, and multibay widths.

Environmental Data

Outlines data center acclimation times, operating, and shipping/storage environment specifications.

Power and Cooling Data

Details DMX-3 system power consumption and heat dissipation for various configurations.

Electrical Specifications and Power Requirements

Covers power connections, North American and international specifications, and cable details.

Appendix B: Power Sequences

Vaulting

Explains the vaulting procedure to preserve cache contents during powerdown.

Routinely Powering Up the Symmetrix DMX-3

Provides steps for powering up the system after routine power down via PDP switches.

Powering Down the Symmetrix DMX-3

Details the procedure for powering down the Symmetrix DMX-3 using PDP power switches.

Appendix C: Planning and Installation

Planning Overview

Reviews physical details, EMC personnel tasks, and customer responsibilities for installation.

Symmetrix DMX-3 Power Requirements

Details the three-phase AC power needs, power zones, and customer responsibilities for PDUs.

System Placement Options

Discusses installation in nonraised or raised floor environments, including floor loading requirements.

Planning Host Connectivity

Covers planning for Fibre Channel, iSCSI, ESCON, and FICON connections.

Open Systems Installations

Provides hardware and host checklists for connecting to open systems hosts.

Mainframe Systems Installations

Provides hardware and host checklists for connecting to mainframe systems hosts.

Preface

Important Information

Refers to release notes for up-to-date information and contact EMC for issues.

Audience

Identifies the intended users of the manual: storage administrators and system programmers.

Related Documentation

Provides information on contacting EMC Sales or visiting the EMC Powerlink website.

Conventions Used in This Guide

Explains typographical conventions for notes, cautions, warnings, and danger notices.