Xserve RAID
Technology Overview
January 2004
9688/me v5
1.5.2004 8:30pm
Contents
Page 3 Introduction
Page 4 Product Overview
Key Features
High-Availability Design
Page 7 RAID Basics
RAID Techniques
RAID Levels
Page 12 Deploying Xserve RAID
Xserve RAID Applications
Page 14 Management and Monitoring
Setting Up and Managing Arrays
Monitoring Xserve RAID Systems
Managing Volumes
Page 17 System Architecture
Drive Technology and Capacity
Passive Midplane Data Path
RAID Controllers
Fibre Channel Interconnect
High-Availability Features
Page 23 Service, Support, and Training Options
Page 25 Purchasing Information
Page 27 Technical Specifications
Technology Overview 2
Xserve RAID
Introduction
Last year, Apple introduced Xserve RAID, a high-availability, high-performance storage
solution at a groundbreaking price. With massive capacity and industry-leading remote
management capabilities in a compact 3U enclosure, Xserve RAID put powerful RAID
features within easy reach—an ideal solution for near-line and disk-to-disk storage, as
well as for protecting business- and mission-critical data.
The new Xserve RAID builds on the success of its predecessor with even more
capacity, industry-standard SFP connectors, and advanced management functions.
Apple has worked with leading storage infrastructure vendors to certify Xserve RAID
for integration with existing Fibre Channel hardware and data management solutions.
What’s more, Xserve RAID is now qualified for use in Linux, Windows, and mixedplatform
environments.2
At the heart of Xserve RAID is an innovative Apple-engineered architecture, with
14 high-performance drive channels, dual independent RAID controllers, and a dual
2Gb Fibre Channel host interface. Together they provide up to 3.5TB of storage1 that
can “grow as you go” and throughput of up to 400 megabytes per second.3 Robust
monitoring and notification features and hot-swappable components keep your data
online and available. And with intuitive tools for quick configuration of protected
storage volumes, this revolutionary RAID solution delivers ease of use that could
come only from Apple.
High-performance, high-availability storage has never been so affordable.With a low
price, simplified administration, easy serviceability, and flexible deployment options,
Xserve RAID is designed to protect your organization’s bottom line, as well as your
digital assets.
Technology Overview 3
Xserve RAID
What’s New?
• Larger, 250GB drive modules for even more
capacity—up to 3.5TB of storage per 14-drive
system1
• Industry-standard SFP (Small Form-factor
Pluggable) connectors for additional
deployment flexibility in optical or copper
infrastructures
• Advanced capabilities such as LUN slicing
and online expansion
• Certification of compatibility by leading
storage infrastructure vendors
• Qualification for use in Linux, Windows, and
mixed-platform environments
Product Overview
Key Features
Xserve RAID is a cost-effective answer to the growing storage requirements of businesses
and institutions everywhere. Its high-performance, high-availability features include:
Massive storage. Xserve RAID holds up to 14 hot-swappable Apple Drive Modules—
now with 3.5TB of total storage—in a rack-optimized 3U enclosure. Each 250GB hard
drive connects to a dedicated ATA drive channel, eliminating a traditional source of
bottlenecks and maximizing the 400MB/s Fibre Channel host connection. By adding
more Xserve RAID systems, you’ll have virtually limitless expansion capabilities:
A standard 42U rack can hold over 49TB of Xserve RAID storage.4
Advanced data protection. The high-availability architecture and dual independent
RAID controllers support RAID levels 0, 1, 3, 5, and 0+1. Xserve RAID also supports hybrid
RAID levels 10, 30, and 50 when used in conjunction with host-based software RAID.
High-availability design. To ensure availability of your critical data, Xserve RAID is
designed for nonstop operation. Redundant hot-swappable power and cooling modules
allow the system to keep functioning even if one module fails. All the active components
are modular, making it easy to replace them in seconds—usually without any interruption
of service—and with no tools required. In the event of a failed drive, a global hot spare
provides automatic rebuilding of data, without administrator intervention.5
Fast data access. With sustained throughput of up to 336MB/s, the advanced Xserve
RAID architecture delivers fast access to storage without compromising data integrity.6
Dual independent RAID controllers provide protected storage with unprecedented
performance. In fact, Xserve RAID boasts a throughput at RAID level 5 that’s fast enough
to support real-time, 10-bit high-definition (HD) 1080i video editing.
Intuitive management and monitoring tools. Sophisticated remote management
capabilities dramatically simplify setup and monitoring of RAID storage. The Java-based
RAID Admin application can build RAID sets on the fly, allowing administrators to bring
protected storage online instantly, without waiting for initialization. RAID Admin also
provides continuous feedback on system activity and health. If a problem is detected,
the remote monitoring software automatically sends notification via email or pager,
so administrators can quickly identify problems and repair them without downtime or
data loss.
Server-class support products. To minimize downtime, Apple offers a suite of enterpriseclass
support products, including onsite hardware repairs, advanced software support,
and convenient spares kits.
Technology Overview 4
Xserve RAID
Xserve G5
Xserve RAID works seamlessly with the new
Xserve G5, Apple’s high-density 1U rackoptimized
server. Equipped with single or
dual PowerPC G5 processors, Xserve packs
phenomenal power and a rich feature set
into an affordable, easy-to-deploy system.
Xserve RAID
Xserve RAID combines leading-edge storage
technologies for massive capacity, fast
performance, and superior data protection.
High-Availability Design
The 3U Xserve RAID enclosure is built for reliability, availability, and serviceability
with high-quality, Apple-engineered construction. LEDs on the front panel provide
continuous visual feedback on system status and activity levels; and 14 drive bays
support hot-swapping of drive modules. The back panel features easy access to
redundant RAID controllers and field-replaceable power, cooling, and battery modules,
as well as connectivity to one or more host computers and up to two uninterruptible
power supply (UPS) devices.
Technology Overview 5
Xserve RAID
Apple Fibre Channel PCI Card
Xserve RAID connects to a host Xserve or
Power Mac system using the dual-port 2Gb
Apple Fibre Channel PCI Card (sold separately)
with throughput of up to 400MB/s.3 The Fibre
Channel interconnect technology supports
multiple application environments using
point-to-point, loop, and fabric technologies.
1
3
4
5
6
2
Apple Drive Modules. Xserve RAID holds up to 14 hot-swappable Apple Drive
Modules. Each 250GB drive is on an independent channel to maximize data throughput
and increase system reliability. LEDs on the front of each module indicate drive
health and activity.
System lock. A built-in lock secures the drive modules in the system. The remote
monitoring application shows the status of enclosure security and can notify the
administrator if someone unlocks it.
Unit identifier. Duplicate system identifier buttons on the front and back of the system
can be turned on manually or by using the remote monitoring software, making
it easy to locate a particular Xserve RAID in a rack with multiple devices. The buttons
also illuminate if a system event occurs.
Alarm silencer. In the event of a component failure, the alarm system is triggered;
with a touch of this button, the alarm is silenced. The remote monitoring software
provides detailed event information about the affected system and notifies the
administrator via email or pager.
System status indicators. Indicator lights display status for power supplies, cooling
modules, RAID controllers, and system temperature.
System activity indicators. Forty-six blue LEDs provide at-a-glance activity levels for
each host channel, and Fibre Channel indicators provide link status information.
Front View
2 3 4 5 6 5
1
Technology Overview 6
Xserve RAID
Convenient replacement modules
Problem resolution is fast with AppleCare
Service Parts Kits for Xserve RAID (sold
separately). Each kit has an Apple Drive
Module, power supply module, cooling
module, and RAID controller module.
Back View
5 1 2 3 4 5
7
1
3
4
5
6
7
2
RAID controller modules. Two independent storage processor units manage RAID
functions, data transfers, and failure protection for each set of seven drives. The environment
management coprocessor in each controller simplifies configuration and
management of RAID sets.
Serial ports. Standard DB-9 serial ports allow connection to UPS units for protection
from brownout or over-voltage conditions.
Ethernet ports. The 10/100BASE-T Ethernet interfaces allow you to manage, monitor,
and diagnose Xserve RAID systems over TCP/IP.
Fibre Channel ports. Each RAID processor connects to the host system via a 2Gb
Fibre Channel interface with throughput of up to 200MB/s per port.3 Throughput
is guaranteed, which means bandwidth remains constant, even as more devices are
added in a fabric configuration. Industry-standard SFP connectors support both
optical and copper infrastructures.
Optional batteries. Cache Backup Battery Modules can provide more than 72 hours
of backup power to protect the integrity of data in the RAID controller cache during
a power outage.
Power supply modules. Either of the redundant, load-sharing power supplies can
power Xserve RAID should the other one fail. A failed power supply can be replaced
in seconds without tools and without shutting down the system.
Cooling modules. Redundant, hot-swappable cooling modules provide automatic
front-to-rear cooling for rack environments.
6
RAID Basics
Redundant array of independent disks, or RAID, is a grouping of multiple physical
hard drives into an array, or RAID set, that appears to the host computer as a single
logical storage unit. Use of RAID technology enables organizations to increase storage
capacity while achieving levels of performance, reliability, and data protection not
possible from a single hard drive. All drives in the array can operate simultaneously for
dramatically faster overall throughput. RAID systems can also improve data availability
and fault tolerance, because redundant data can be stored on multiple physical drives.
Even in the event of a drive failure, the system can continue to operate without loss of
data and with no interruption in service.
RAID Techniques
RAID technology is based on three practices: Striping to improve storage performance,
and mirroring and parity to provide redundancy for increased data protection. Most
RAID configurations, or RAID levels, combine these techniques to provide a balance
of data protection and performance.
Striping
Increased performance in a set of multiple drives is accomplished by data striping.
As the name implies, striping divides a logical drive into data blocks, or stripes, that
are distributed across the array of physical drives. Data is then laid down according
to the stripe paths, so that each file is spread across multiple drives. Striping a set
of disks greatly improves overall storage performance because the drives operate in
parallel. While one drive is writing or reading a data block, another is seeking the next
block. Striping alone, known as RAID level 0, offers no data protection.
Mirroring
The simplest method of achieving data redundancy, mirroring involves writing identical
copies of all data to a pair of physical drives. This results in very high data reliability: If
one drive fails, the data is still available on the remaining disk drive. However, it also
results in storage efficiency of only 50 percent, because two physical drives are required
to create a protected storage volume with the equivalent capacity of a single drive.
Mirroring alone is known as RAID level 1.
Parity
A more sophisticated method of creating redundancy, parity provides data protection
for an array of drives without requiring complete duplication of the drive contents.
Parity information can be used—along with the data on the surviving drives—to
reconstruct the contents of a failed drive. The parity data can be stored on a dedicated
drive, as in RAID 3, or distributed across an array of drives, as in RAID 5. In either case,
parity provides much greater storage efficiency than mirroring—up to 85 percent for
a set of seven drives.
Technology Overview 7
Xserve RAID
Software versus hardware RAID
RAID functionality can be implemented
in hardware or software. Software RAID—
available in Mac OS X and Mac OS X
Server—enables drive striping and drive
mirroring, whether for basic RAID 0 or
RAID 1 configurations or for robust configurations
using hybrid RAID levels 10, 30, or
50. Software RAID is not recommended for
parity RAID levels, such as RAID 3 and 5,
which involve compute-intensive calculations
that can overtax the system processor.
RAID Levels
Each RAID level offers a unique balance of I/O performance, data protection, and storage
efficiency. Xserve RAID supports all popular RAID levels, so you can select the best
configuration for your application and your budget.
Comparison of RAID levels
RAID level Minimum Storage Read Write Data
number of efficiency performance performance redundancy
drives required
RAID 0 2 Highest Very high Highest No
RAID 1 2 Low High Medium Yes
RAID 3 3 High to very high Medium Medium Yes
RAID 5 3 High to very high High High Yes
RAID 0+1 4 Low High High Yes
RAID 10 4 Low High High Yes
RAID 30 6 High to very high High High Yes
RAID 50 6 High to very high Highest Very high Yes
Each RAID level offers a unique balance of performance, data protection, and drive efficiency.
The efficiency of parity RAID levels increases with the number of drives in an array.
RAID 0: Striping
RAID 0 distributes data evenly in horizontal stripes across an array of drives.While
RAID 0 offers substantial speed enhancements, it provides no data protection: If one
drive fails, all of its data is lost and all drives must be reformatted. RAID 0 provides the
most efficient use of drive capacity, because no storage space is dedicated to redundant
data or parity information.
RAID 0, or drive striping, breaks a single file into data blocks and distributes it across
two or more drives.
Stripe 10
. . .
Stripe 7
Stripe 4
Stripe 1
Stripe 11
. . .
Stripe 8
Stripe 5
Stripe 2
Disk 1 Disk 2
Stripe 12
Stripe 9
Stripe 6
Stripe 3
Disk 3
. . .
Technology Overview 8
Xserve RAID
RAID 0
RAID 1: Mirroring
RAID 1 creates a pair of mirrored drives with exactly the same data. It provides a high
level of data availability and, by using both drives simultaneously, offers fast read performance.
Write speeds are lower, however, because all data is written twice—once to
each drive. RAID 1 is also relatively expensive to deploy because it offers the poorest
level of drive efficiency.
Mirrored drives in RAID 1 contain identical sets of data for total redundancy.
RAID 3: Striping with parity
RAID 3 stripes data across two or more drives and stores parity data on a dedicated
drive. In the event of a disk failure, the redundant parity bits can be used to reconstruct
data on any drive. RAID 3 offers fast read rates and high data availability, with greater
storage efficiency than RAID 1.Write performance in RAID 3 is faster than in RAID 1, but
not as fast as in RAID 5, because it depends on the availability of a separate parity drive.
RAID 3 requires a minimum of three drives; using more drives results in faster performance
and greater drive efficiency.
RAID 3 stripes data across two or more drives and stores parity data on a dedicated drive.
Stripe 10
. . .
Stripe 7
Stripe 4
Stripe 1
Stripe 11
. . .
Stripe 8
Stripe 5
Stripe 2
Disk 1 Disk 2
Stripe 12
. . .
Stripe 9
Stripe 6
Stripe 3
Disk 3
Parity 1–3
Parity 4–6
Parity 7–9
Parity 10 –12
Disk 4
Parity generation
. . . . . .
Stripe 4
. . .
Stripe 3
Stripe 2
Stripe 1
Stripe 4
. . .
Stripe 3
Stripe 2
Stripe 1
Disk 1 Disk 2
=
Technology Overview 9
Xserve RAID
RAID 3
RAID 1
RAID 5: Striping with distributed parity
RAID 5 distributes both data and parity information across an array of drives one
block at a time, with each drive operating independently. This enables maximum read
performance when accessing large files and improves performance in a transactionprocessing
environment.Write performance is also improved because parity information
is striped across the drives, removing the bottleneck of a single parity drive.
RAID 5 is the most popular configuration for high-throughput protected storage. Like
RAID 3, RAID 5 requires a minimum of three drives; using more drives provides faster
performance and higher storage efficiency.
RAID 5 distributes data and parity information across all the drives in an array.
RAID 0+1: Striping over mirroring
This hybrid RAID level is created by striping data across multiple pairs of mirrored
drives.With Xserve RAID, both striping and mirroring are set up in hardware, which
means the array can run independently of the server processor. RAID 0+1 provides
higher throughput with simpler setup than protected configurations that use software
RAID for striping, such as RAID 10.
Xserve RAID offers a hardware RAID level 0+1, which mirrors drive pairs and then stripes
data across the mirrored sets.
Stripe 7
Stripe 5
Stripe 3
Stripe 1
Stripe 7
. . .
Stripe 5
Stripe 3
Stripe 1
Disk 1 Disk 2
Mirrored pair
Striped pairs
Mirrored pair
=
Stripe 8
. . .
Stripe 6
Stripe 4
Stripe 2
Stripe 8
. . .
Stripe 6
Stripe 4
Stripe 2
Disk 3 Disk 4
=
Stripe 12
Stripe 9
. . .
Parity 10 –12
. . .
Stripe 7
Stripe 4
Stripe 1
Stripe 10
. . .
Parity 7–9
Stripe 5 Stripe 6
Stripe 2
Disk 1 Disk 2
Stripe 11
. . .
Stripe 8
Parity 4–6
Stripe 3
Disk 3
Parity 1–3
Disk 4
Parity
generation
. . .
Technology Overview 10
Xserve RAID
RAID 0+1
RAID 5
RAID 10, 30, and 50
Hybrid RAID levels 10, 30, and 50 use hardware RAID to create two or more sets in RAID
1, 3, or 5, and software RAID to stripe across the sets. This creates a single data volume
with the best balance of performance and data protection. In the case of Xserve RAID,
you can combine all 14 drives for high performance at maximum capacity.
Technology Overview 11
Xserve RAID
Stripe 12
Stripe 9
Parity 10–12
. . .
Stripe 7
Stripe 4
Stripe 1
Stripe 10
. . .
Parity 7–9
Stripe 5 Stripe 6
Stripe 2
Disk 1 Disk 2
RAID 5 set Striped sets
Stripe 11
. . .
Stripe 8
Parity 4–6
Stripe 3
Disk 3
Parity 1–3
Disk 4
Parity
generation
. . .
Stripe 12
Stripe 9
. . .
Parity 10 –12
. . .
Stripe 7
Stripe 4
Stripe 1
Stripe 10
. . .
Parity 7–9
Stripe 5 Stripe 6
Stripe 2
Disk 5 Disk 6
RAID 5 set
Stripe 11
. . .
Stripe 8
Parity 4–6
Stripe 3
Disk 7
Parity 1–3
Disk 8
Parity
generation
. . .
RAID 50
This RAID 50 configuration uses software RAID to stripe data across two RAID 5 sets, which are created using hardware RAID.
Deploying Xserve RAID
Exponential growth in the creation and distribution of digital content is driving
demand for high-capacity storage solutions. Large databases, digital video footage,
immense scientific data sets, and expanding archives of financial information and
employee records require terabytes of storage. At the same time, data protection
and near-instant data access are crucial to many organizations. In response to these
pressing requirements, customers have been forced to make tradeoffs among data
protection, performance, and capacity—or spend hundreds of thousands of dollars
on high-end storage solutions that combine these features.
Xserve RAID is a revolutionary storage product that eliminates the need for these
tradeoffs. With massive capacity and high-availability features previously available only
in much more expensive storage systems, Xserve RAID offers unmatched versatility
at an unprecedented price. What’s more, it meets the most demanding performance
requirements, delivering a sustained throughput of up to 336MB/s—the highest of
any RAID system in its class.6 These robust capabilities make Xserve RAID ideally suited
for protecting mission- and business-critical data, yet it’s affordable enough for nearline
storage deployments and fast enough for media production environments.
Comparison of storage solutions
Apple Dell IBM HP Sun
Xserve RAID EMC CX200 FASt200 StorageWorks StorEdge
3542-1R 1000 6120
Capacity 3.5TB 2.1TB 2.1TB 2.1TB 2.04TB
Size 3U 3U 3U 3U Two 3U
Price* $10,999 $18,999 $51,895 $23,925 $74,600
Price per GB $3.14 $9.05 $24.71 $11.39 $36.57
* Based on prices published on resellers’websites on December 10, 2003.
Compared with leading storage products, Xserve RAID offers the lowest cost per gigabyte.
At the same time, it packs more gigabytes in less space—up to 3.5TB in a 3U enclosure.1
Xserve RAID Applications
Whether in all-Apple or heterogeneous environments, Xserve RAID can fit into existing
storage networks or provide a foundation for new deployments. The industry-standard
SFP-based Fibre Channel interface supports point-to-point, loop, and fabric topologies
for integrating Xserve RAID into Fibre Channel storage infrastructures. In addition, a
platform-independent design and Java-based administrative tools make setup and
monitoring easy from virtually any Internet-connected computer. Now certified by
leading storage network manufacturers and qualified to work with popular operating
systems, Xserve RAID is a flexible solution for a full range of storage applications.
Technology Overview 12
Xserve RAID
Xserve RAID: A unique blend of features
A robust feature set and highly flexible
deployment options make it possible
to use Xserve RAID in a wide range of
environments, including:
• Mission-critical data storage deployments,
where zero downtime is paramount at
virtually any cost
• Business-critical data storage deployments,
which require high capacity and high
availability at a reasonable cost
• Near-line archive deployments, which
seek a balance of high capacity, scalability,
and reasonable throughput at the lowest
possible cost
• Rich media storage deployments, which
require superfast throughput, data protection,
large capacity, and a reasonable cost
Primary storage for Mac,Windows, and Linux servers
With high-availability features such as redundant power and cooling, protected RAID
storage, global drive hot sparing, and hot-swap components, Xserve RAID delivers fast,
reliable data access—meeting the requirements of the most demanding businesscritical
and mission-critical storage deployments. It also provides the capacity and
deployment flexibility required for High Performance Computing (HPC) environments.
At the same time, Xserve RAID offers industry-leading capacity, up to 3.5TB,1 and can
support dozens of servers using advanced LUN slicing and mapping capabilities. Best
of all, this outstanding feature set is available at a cost far below that of competing
primary storage products.
Network Attached Storage (NAS)
Xserve RAID teams with Xserve G5, Apple’s easy-to-deploy 1U server, to provide an
affordable alternative to traditional Network Attached Storage devices. Offering the
compatibility of open standards and Apple’s legendary manageability, this highperformance,
high-capacity solution allows Mac, Windows, and Linux clients to
share terabytes of information—with no per-user licensing fees. At the same time,
Xserve RAID has the flexibility to fit easily into existing mixed-platform Storage Area
Networks (SANs).<
Near-line and disk-to-disk archive
Xserve RAID offers outstanding value for near-line applications, while providing the
ready data access required by many governmental regulations for email and HR
records. Fibre Channel connectivity provides simple and flexible attachment to existing
Fibre Channel networks and SAN infrastructures. Near-line storage users get the
benefit of low-cost, high-capacity storage, without sacrificing high availability and
data protection. Xserve RAID also offers superior throughput and scalability compared
with other systems typically used for near-line storage.With Xserve RAID, organizations
can reduce their overall storage costs, as well as their dependence on inflexible,
proprietary systems.
Rich media storage
With a video-optimized architecture and dual independent 2Gb Fibre Channel interface,
Xserve RAID is the perfect complement to a Power Mac G5 video editing workstation.
It provides the fast, consistent performance—up to 336MB/s sustained
throughput—required for video post-production. In fact, Xserve RAID delivers enough
bandwidth for working in high-definition (HD) video or supporting multiple streams
of uncompressed standard-definition (SD) video with real-time effects. In addition,
with up to 3.5TB of online storage, Xserve RAID makes it easy to manage multiple
video tasks. Even when used for editing in uncompressed HD 1080i, this robust
storage system can hold nearly 16 hours of footage.What’s more, Xserve RAID scales
in both throughput and capacity: Users need only purchase the performance level
and capacity they require today, with the assurance that their investment will be
protected as application and storage needs grow.
Technology Overview 13
Xserve RAID
Third-party certifications
Leading storage infrastructure vendors have
certified Xserve RAID for integration with
existing Fibre Channel hardware and data
management solutions, including:
• Veritas
• QLogic
• Brocade
• Chaparral Network Storage
• ATTO
• Emulex
• Candera
In addition to Mac OS X and Mac OS X Server,
Xserve RAID has been qualified for use on
these operating systems:
• Windows Server 2003
• Red Hat Enterprise Linux v2.1 and v3
• Yellow Dog Linux v3
Management and
Monitoring
Xserve RAID comes with RAID Admin, a powerful remote management application
that dramatically simplifies setup and monitoring of multiple Xserve RAID systems. This
Java-based tool provides an intuitive interface for creating protected storage volumes,
managing preferences, and monitoring storage hardware. To protect storage systems
from unauthorized access, RAID Admin uses robust, multilevel password authentication.
RAID Admin integrates with hardware to continuously monitor system activity and
status. The environment management coprocessors in the RAID controllers connect to
the host system via Ethernet, providing dedicated, out-of-band system management
capabilities. This ensures optimum system performance and reliability, because there is
no contention for bandwidth with the RAID processors or the Fibre Channel interface.
Setting Up and Managing Arrays
RAID Admin lets you create arrays in three easy steps. First, choose a RAID level for
information about the benefits and limitations of that level. Next, click the drives you
want to assign to the array. RAID Admin even gives you information about each of
the drives in your Xserve RAID system, so there’s no guesswork. Any remaining drives
are assigned as global hot spares for each controller. Last, choose background initialization
to make the newly created array available immediately.
RAID Admin provides an easy-to-use interface for creating RAID sets on the fly.
Technology Overview 14
Xserve RAID
Remote management using RAID Admin
The Java-based RAID Admin application
works over TCP/IP, making it easy to
set up, manage, and monitor Xserve
RAID systems from virtually any Internetconnected
computer.
Automatic discovery with Rendezvous
Using Apple’s Rendezvous technology,
RAID Admin automatically discovers Xserve
RAID systems on your network. This makes
it easy to add them to your management
window, without needing to enter each IP
address manually.
Expanding arrays
Once an array is established, you can easily add more disks using RAID Admin. Expanding
an array preserves the existing array, while making available the capacity of the added
drives. Expansion in RAID Admin works “on the fly,” so the expanded capacity is available
within minutes.
Slicing arrays
To share a single RAID set across multiple servers, RAID Admin allows you to divide it into
smaller segments, or “slices.” Each slice becomes a separate LUN, or logical unit number,
so the host system can manage it as a discrete volume. Instead of creating many small
arrays for individual servers, this “pooling and distributing” technique enables administrators
to leverage the storage efficiencies of a large consolidated array. RAID Admin can
slice up to eight LUNs per RAID controller, or up to 16 LUNs per Xserve RAID system.
LUN mapping
RAID Admin offers advanced Fibre Channel networking features such as LUN mapping
and masking.When you connect an Xserve RAID to more than one host system on a
Fibre Channel network, you can “map” each LUN on the RAID system to a single host and
“mask” it from any other host. By masking arrays and slices, you avoid the possibility that
more than one host will write data to an array, eliminating the risk of array corruption or
An intuitive interface makes it easy to set LUN mapping, as well as other storage options.
Monitoring Xserve RAID Systems
Xserve RAID features robust self-monitoring technology that maximizes storage availability
while minimizing the pressure on system administrators. RAID Admin software
reports at-a-glance information about all Xserve RAID systems on the network, with
green, yellow, or red icons indicating the health of each subsystem. Administrators can
easily “drill down” for detailed information about status and performance of each component.
If operating conditions for any subsystem exceed predefined thresholds, RAID
Admin can automatically notify the administrators via email, pager, or email-capable cell
phone—allowing them to stay in touch with storage deployments and resolve issues
without downtime or data loss.
Technology Overview 15
Xserve RAID
RAID Admin software displays summary health and activity information for multiple
Xserve RAID systems.
Managing Volumes
Administrators can use host-based volume management tools to mount storage
volumes on host systems. In Mac OS X or Mac OS X Server, they can use Disk Utility
to initialize arrays in Mac OS Extended or UNIX File System formats; turn on file
system journaling; and set up software RAID arrays.
Disk Utility makes it easy to use software RAID to create hybrid RAID levels 10, 30, and 50.
Technology Overview 16
Xserve RAID
File system journaling in Mac OS X Server
A robust file system journaling feature in
Mac OS X and Mac OS X Server enhances
the availability and fault resilience of
servers and server-attached storage devices.
Journaling protects the integrity of the
Mac OS Extended (HFS+) file system in the
event of an unplanned shutdown or power
failure and maximizes uptime by expediting
repairs to the affected volumes when the
system restarts.
System Architecture
Fast throughput and data availability are paramount for dedicated storage systems.
That’s why Xserve RAID combines leading-edge Fibre Channel, RAID, and ATA technologies
in an innovative architecture designed for superior performance and
reliability. Redundant, hot-swappable components and a passive midplane data path
protect your digital assets from single points of failure, while independent controllers
and 14 drive channels provide high-speed throughput for delivering data quickly to
the host system.
Technology Overview 17
Xserve RAID
Xserve RAID Architecture
7
1
13
4
3
2
11
5 6 8 9 10
12
Apple Drive Modules
Independent ATA drive channels
Drive controllers
RAID controller modules
Cache memory
Dual independent RAID processors
Fibre Channel ports
Redundant environment managers
Ethernet ports
Serial ports
Redundant cooling modules
Redundant power supplies
Cache Backup Battery Modules (optional)
1
3
2
4
5
7
6
8
9
11
10
12
13
Drive Technology and Capacity
Instead of relying on expensive SCSI or Fibre Channel hard drives, Apple developed
a high-throughput ATA to Fibre Channel storage architecture that delivers superior
performance and reliability at a much lower cost. Xserve RAID achieves its massive
3.5TB capacity with 14 hot-swappable 250GB Apple Drive Modules. The high-capacity
7200-rpm ATA/100 drive modules provide affordable expansion and configuration
flexibility as storage needs grow.
Fourteen independent drive channels
The multithreaded Xserve RAID architecture features a dedicated ATA/100 channel
for each of its 14 drive bays. Drive independence prevents data bottlenecks and
maximizes throughput while enhancing availability. Because each hard drive is isolated
on its own bus, a drive failure doesn’t degrade the accessibility or performance of the
surviving drives. In addition, independent drive channels reduce the complexity and
cost of high-availability storage, since loop redundancy circuits and signal amplifiers
aren’t required, as in multidrive Fibre Channel and SCSI implementations.
Apple Drive Modules
Hot-plug Apple Drive Modules feature a unique handle design for fast, easy installation
and a positive locking mechanism to hold them tightly in place after insertion.
Sophisticated connectors called SCA II, or Single Connector Attachment II, protect the
connecting pins from bending when a drive is inserted or removed. Carefully tested
and qualified to ensure maximum performance and reliability, Apple Drive Modules
work seamlessly with RAID Admin, Apple’s innovative remote management and
monitoring software for Xserve RAID.
On-drive cache
Each Apple Drive Module is equipped with 8MB of disk cache to accelerate read and
write operations in performance-sensitive applications such as video editing. On-drive
read cache, commonly called “read-ahead” cache, allows the drive controller to retrieve
a block of data before it is required by the host system. The RAID controller provides
instructions to each drive in an array, indicating what data block is required next and
allowing the individual drive controllers to queue up the data for instant availability.
Similarly, on-drive cache can serve as a holding tank for write data. When this option
is enabled, the RAID controller distributes data to each drive and stores it in cache—
allowing the drive controller to notify the RAID processor immediately that transmission
was successful, also known as a “committed write.” This frees up the storage
pipeline for other needs while the data is being written to the drive platters at
maximum speed.
Using on-drive write cache is inherently risky: In the event of a power failure, the
cached data could be lost. For this reason, it is turned off by default in protected
RAID configurations.
Hot-swapping capabilities
The hardware RAID controllers and Apple-designed drive carriers enable true hotswapping
of Apple Drive Modules. This means a failed drive can be removed and
replaced without interruption in service or loss of data. The system continues to
operate while the contents of the failed drive are rebuilt on a replacement drive
using redundant or parity information. (This feature is not applicable to a RAID 0
configuration, since it doesn’t offer data protection.)
Technology Overview 18
Xserve RAID
Apple Drive Modules
Xserve RAID uses reliable, highperformance
Apple Drive Modules
with true hot-swapping capabilities.
Monitoring of drive health
Xserve RAID hardware and remote management software work together to provide
industry-leading monitoring and alerting capabilities. The RAID controller automatically
reads Self-Monitoring, Analysis, and Reporting Technology (SMART) data, which
allows each hard drive to report its health. This enables the operating system to
warn the administrator of a prefailure condition, providing the opportunity to replace
the hard drive before the failure occurs. Each drive module has two LEDs for local
monitoring of drive activity and health.
Passive Midplane Data Path
The Xserve RAID architecture is designed to avoid vulnerability to a single point of
failure. This means that the failure of any single component can’t result in a systemwide
failure and loss of data availability. For highest reliability, Apple built Xserve
RAID around a midplane that serves as a passive data path. The midplane is the
central connector between the drives, RAID controllers, power supplies, and cooling
modules. Most RAID systems depend on the midplane to relay data and instruction
sets between drives, and a failure in the midplane can impair data availability. In
Xserve RAID, all data passes through the independent drive channels, which are
simply held in place by the midplane. This design improves system reliability and
protects the availability of stored data.
RAID Controllers
Xserve RAID features two controllers that independently manage storage operations
for a set of up to seven drives. Dual independent controllers allow for simultaneous
storage processing. Because each controller needs to manage only seven drives,
Xserve RAID delivers outstanding performance that scales as capacity increases. These
controller modules offer advanced availability and manageability features, including
the environment manager, which manages RAID functions and monitors status and
activity of system components.
RAID processor
Each Xserve RAID controller has a powerful processor that manages all the data
transfers between the hard drives and host computer. It performs the complex parity
calculations required for RAID levels 3 and 5, generating parity data on the fly while
managing write operations to each drive in the set. In the event of a drive failure,
the RAID processor uses redundant data to rebuild its contents on a spare drive.5
Xserve RAID supports RAID levels 0, 1, 3, 5, and 0+1 using the RAID processor, as well
as hybrid RAID levels 10, 30, and 50 by combining hardware RAID capabilities with
host-based software RAID.
An innovative process ensures that RAID sets are error-free and tuned for maximum
throughput. When creating a RAID set, Xserve RAID verifies the integrity of the array
by checking every block on every disk for potential errors. If a bad block is discovered,
it simply chooses another block that’s in close proximity to the original—eliminating
unnecessary head movement that can result in lower performance.
To maintain optimal throughput, the RAID processor uses another special technique
that retrieves data on the first revolution of the RAID set. This avoids multiple retries
(an activity that can hamper performance on RAID systems), while allowing Xserve
RAID to maintain a nearly constant sustained throughput over the entire platter
of each hard disk. Outer and inner tracks perform comparably, providing consistent,
fast delivery of data to the host system. This is particularly critical in high-bandwidth
applications such as HD video editing, which requires fast storage throughput for
clean video capture and smooth playback.
Technology Overview 19
Xserve RAID
Controller cache memory
Each RAID controller is equipped with 128MB or 512MB of cache memory for enhanced
storage throughput. For optimal read performance, streaming data can be queued
into cache, and sophisticated algorithms measure data traffic patterns and re-allocate
read cache dynamically. Depending on write performance and data protection requirements,
cache memory can be configured as “write-back” or “write-through.” In either
case, the write cache configuration does not affect read cache settings.
Write-back cache. For performance-critical applications, cache memory can accelerate
write speeds using a configuration called write-back cache. In this mode, data is considered
committed, or successfully received, as soon as the RAID controller writes
back to the host that the information is stored in cache memory. However, as with
drive cache, write-back cache is vulnerable to data loss. Since cached data is stored in
SDRAM, which requires a continuous supply of power, a power outage or major system
failure could result in data loss. This risk can be minimized by connecting a UPS system
or using the optional Cache Backup Battery Modules. With a minimum of 72 hours of
power, the battery modules preserve the contents of cache memory until system power
is restored.
Write-through cache. When write-through cache is enabled, the RAID controller
writes data through the cache, directly to the disks, before informing the host that the
write is committed. Although this may reduce performance, write-through cache is the
recommended setting for protected RAID without a battery or UPS device. For highbandwidth
applications or when multiple servers are attached to Xserve RAID, writeback
cache is recommended. If a power outage occurs while using write-back cache
with a UPS system, Xserve RAID automatically reverts to write-through cache to protect
the data in case of a UPS failure.
Environment managers
Each Xserve RAID controller module contains a special coprocessor that monitors
the enclosure environment and manages configuration of the main processor’s RAID
functions. This innovative environment manager simplifies management and boosts
reliability by ensuring continuous feedback on the status and activity levels of system
components.
The environment managers integrate seamlessly with RAID Admin software and the RAID
processor, providing advanced capabilities such as RAID Now for background initialization
during RAID creation. Each environment manager operates on an independent bus
and communicates with the host system via Ethernet. All the management and monitoring
processes are handled “out of band,” which means Fibre Channel bandwidth is
not specified for management chores.
Each environment manager communicates with both RAID controllers and all hard
drives. If one of the RAID environment managers fails, the other takes over and
continues the monitoring and management functions to avoid any interruption in
service. At the same time, it immediately notifies the administrator via email of the
component failure.
Because the RAID environment managers connect to the host computer over Ethernet
using standard Internet protocols, it’s easy to connect to and monitor Xserve RAID
systems from any computer on the Internet. In addition to an Ethernet port, each
environment manager has a serial port for connecting an optional UPS device, providing
an extra measure of protection against power surges or electrical outages.
Technology Overview 20
Xserve RAID
Fibre Channel Interconnect
Xserve RAID features dual independent 2Gb Fibre Channel ports for fast data transport
between the storage system and the host computer. This industry-standard technology
provides superior bandwidth, availability, and deployment flexibility over SCSI technology.
To ensure interoperability, Xserve RAID uses the latest industry-standard SCSI 3
protocol for data transfer. In addition, SFP (Small Form-factor Pluggable) connectors
support low-cost copper cables, long-distance optical cables, or copper cables with
embedded SFP transceivers and work with industry-standard Fibre Channel switches.
400MB/s throughput
Each 2Gb Fibre Channel port offers 200MB/s bandwidth for a total throughput of up
to 400MB/s.3 Fibre Channel is the only storage connectivity technology that provides
guaranteed bandwidth, so the host computer receives data at the same high speed as
the RAID system sends it.
Superior scalability
Unlike with Gigabit Ethernet or SCSI technologies, adding storage units to a Fibre
Channel network doesn’t lead to congestive data loss or reduced overall bandwidth.
The highly scalable Fibre Channel technology can address up to 126 devices per loop,
with each device experiencing a full 200MB/s throughput. In contrast, SCSI allows for a
maximum of only 15 devices per channel, resulting in added expense and complexity
to deploy large RAID arrays.
Long-distance connectivity
Xserve RAID connects to a 2Gb Fibre Channel PCI Card in the host computer via a thin,
flexible copper or fiber-optic cable. The Fibre Channel interface also provides support
for much longer distances between the storage units and the host system than is possible
using SCSI cables. The Apple Fibre Channel PCI Card accepts optical transceivers
allowing it to use fiber-optic cables that can extend 500 meters—particularly valuable
for organizations using Xserve RAID to back up or archive critical data. What’s more,
long-distance connectivity provides the added protection of physical separation in the
event of a major disaster.
High-Availability Features
A modular design that features redundant components and easy serviceability makes
Xserve RAID ideal for operations where data availability is crucial. All active components
are field-replaceable and most are hot-swappable. LEDs on the front and rear
indicate the health of each component: green means OK, yellow indicates warning, and
red signals failure. In the event of a component failure, the remote monitoring system
notifies the administrator via email, allowing repairs to be accomplished in seconds—
usually without shutting down the system.
Redundant components
The environment managers monitor the Xserve RAID enclosure and the status of
system components. If one of the power supplies fails, the other takes over and
powers the system alone until the failed module is replaced. The environment
managers themselves are redundant: Both monitor the entire enclosure and record
status information on all components, enabling automatic adjustments and remote
notifications as needed. If an environment manager fails, the other one takes charge
of monitoring the system.
Technology Overview 21
Xserve RAID
Apple Fibre Channel PCI Card
Xserve RAID connects to an Xserve or
Power Mac host system using the dualport
2Gb Apple Fibre Channel PCI Card
(sold separately). Two 2.9-meter copper
cables are included with the card for
connecting to the two RAID controllers
in the Xserve RAID system.
UPS support
A single Xserve RAID power supply can sustain the system in the event of a power
outage or electrical surge. Each RAID controller has its own DB-9 serial port, allowing
Xserve RAID to connect to and monitor up to two UPS sources. When the system
detects that input power has been switched to a UPS source, it changes the cache
mode from high-performance write-back to safer write-through cache—protecting
data transactions should the UPS fail. If the UPS system is capable of reporting a low
power level, Xserve RAID can alert the administrator of the condition, permitting a
manual shutdown before the power runs out.
Cache Backup Battery Modules
With optional Cache Backup Battery Modules in Xserve RAID, data transactions in the
RAID controller cache are protected for more than 72 hours after an input power failure.
Once power is restored, Xserve RAID writes the transactions and begins recharging
the batteries. If battery power is low, the system remains in write-through cache mode
until the battery charge exceeds 50 percent, when it returns to write-back mode.
Hot sparing
For each RAID controller, any drives not assigned to an array are automatically used
as global hot spares. If a drive fails, the RAID controller rebuilds its data on the spare
drive without requiring intervention by the administrator. The rebuild operation occurs
in the background while the controller processes normal host reads and writes—
so service continues uninterrupted.5 To promote the best mix of performance and
rebuild speed, the rebuild rate varies with the amount of traffic, or fabric load, on the
RAID controller. As soon as the administrator replaces the failed drive, Xserve RAID
configures it as a new global hot spare for the array.
Easy serviceability
Power supplies, cooling modules, RAID controller modules, and hard drives can be
removed and replaced in seconds without tools. These components are all hotswappable,
which means they can be replaced without interrupting data availability.
In addition, Xserve RAID has a shutdown feature that allows for planned maintenance
without running down the cache backup batteries. This feature can also be beneficial
if Xserve RAID is stored for long periods of time.
Technology Overview 22
Xserve RAID
Service, Support, and
Training Options
Every Xserve RAID comes with a one-year limited warranty and 90 days of up-andrunning
telephone support. In addition, the AppleCare website publishes in-depth
product information, training on hardware and software installation and configuration,
and technical resources, including the AppleCare Knowledge Base, discussions, and
downloadable software on Apple’s Featured Software site.
For critical data storage deployments, Apple also offers a comprehensive range of service
and support options for Xserve, Xserve RAID, and Mac OS X Server. For more information
about these AppleCare products, see www.apple.com/server/support.
AppleCare Premium Service and Support Plan
This server-class support product provides up to three years of up-and-running telephone
and email support and onsite hardware service. Apple technical support experts
are available 24 hours a day to help you determine whether you’re experiencing a
hardware failure or a RAID Admin configuration issue. In either case, Apple will work
to get systems up and running quickly.
The AppleCare Premium Service and Support Plan delivers up-and-running telephone
and email support within 30 minutes—24 hours a day, seven days a week. The hardware
repair coverage provides onsite response within four hours during business hours and
next-day onsite response when you contact Apple after business hours (terms apply).7
For added peace of mind, you’ll have the assurance that Apple-authorized technicians
will perform repairs using genuine Apple parts.
The AppleCare Premium Service and Support Plan can be purchased at any time while
Xserve RAID is still under its original one-year warranty. However, since coverage ends
three years after the hardware purchase date, you’ll get maximum advantage when you
make both purchases at the same time.
AppleCare Service Parts Kit
Xserve RAID is designed for quick and easy swapping of crucial parts; no special tools
or training certifications are needed. AppleCare Service Parts Kits let system administrators
keep key components handy to address the most common hardware failures. Each
kit has an Apple Drive Module, a power supply, a cooling module, a RAID controller
module, and a Fibre Channel cable (SFP to SFP). When the AppleCare Premium Service
and Support Plan is combined with an AppleCare Service Parts Kit, technical support
experts can often help troubleshoot and fix systems right over the phone—day or
night—eliminating the need for an onsite technician.
Technology Overview 23
Xserve RAID
Mac OS X Server Software Support
Apple also offers expert consultative phone and email support for Mac OS X Server
integration and migration issues, as well as help with command-line configuration.
Three levels of Mac OS X Server Software Support are available—Select, Preferred,
and Alliance—depending on the number of incidents supported and desired response
time. Each plan provides one year of coverage.
Training and Certification Programs
Apple offers comprehensive instruction on Mac OS X and Mac OS X Server, covering
such topics as client management, system troubleshooting, and cross-platform
network configuration. A combination of lectures, demonstrations, and hands-on
exercises, classes are taught by Apple Certified Trainers with real-world experience
and dynamic presentation skills. Classes are offered at Apple Authorized Training
Centers, as well as at customer locations.
Once IT professionals have acquired the requisite skills, Apple certification programs
provide tangible evidence of their technical expertise. For more information about
Apple training and certification programs, visit www.apple.com/training.
Technology Overview 24
Xserve RAID
Purchasing Information
Standard Configurations
The following standard Xserve RAID configurations are available. You can also order
custom-configured systems with additional Apple Drive Modules and more cach
memory.
Order number M9271LL/A M9272LL/A M9273LL/A
Total available storage—RAID 0 1TB1 1.75TB1 3.5TB1
Usable storage—RAID 1 500GB1 750GB1 1.5TB1
Usable storage—RAID 3 and 5 750GB1 1.5TB1 3TB1
ATA/100 Apple Drive Modules Four 250GB drives1 Seven 250GB drives1 Fourteen 250GB drives1
On-drive cache 8MB per drive 8MB per drive 8MB per drive
Cache memory 128MB per controller 128MB per controller 128MB per controller
Expansion Fourteen drive bays with independent 100MB/s ATA channels for up
to 3.5TB of storage1
Also included Mounting screws with M5, M6, and 10/32-inch threads; caged nuts;
two agency-approved 12-foot power cables
Software Xserve RAID Admin Tools CD
Service and support 90 days of free telephone support and one-year limited warranty;
optional extended service and support products
System Requirements
Xserve RAID connects to the following Apple systems using the Apple Fibre Channel
PCI Card (cables included):
• Xserve G5 or Xserve with Mac OS X v10.2.4, Mac OS X Server v10.2.4, or later
• Power Mac G5 with Mac OS X v10.2.7, Mac OS X Server v10.3, or later
• Power Mac G4 (800MHz or faster) with Mac OS X v10.2.4, Mac OS X Server v10.2.4,
or later
Xserve RAID connects to Windows- and Linux-based systems using a compatible
Fibre Channel PCI card and cables; check with manufacturer for details.
Technology Overview 25
Xserve RAID
Related Products
• Apple Fibre Channel PCI Card with two copper SFP to SFP cables
• 250GB Ultra ATA Apple Drive Modules
• Cache Backup Battery Modules (two)
• Xserve G5, available in single- or dual processor server configurations and
dual processor cluster node configuration
• AppleCare Premium Service and Support Plan
• AppleCare Service Parts Kit
• Third-party products, including racks, fiber-optic cables, SFP transceivers, and Fibre
Channel switches
For up-to-date information on these and other products that enhance Xserve RAID
deployments, visit www.apple.com/store or call 800-MY-APPLE.
Technology Overview 26
Xserve RAID
Technical Specifications
Storage
• Fourteen drive bays on independent 100MB/s channels for up to 3.5TB of total storage1
• Four, seven, or fourteen 250GB 7200-rpm ATA/100 Apple Drive Modules with 8MB disk
cache (standard configurations); empty drive bays contain blank modules
• Support for reading SMART data from Apple Drive Modules for prefailure notification
RAID controllers and cache memory
• Dual independent controllers, each with an environment management coprocessor for
out-of-band remote management and monitoring
• 128MB of cache per controller (256MB total); support for up to 512MB per controller
(1GB total)
• Cache Backup Battery Modules (sold separately) for over 72 hours of memory protection
RAID operation
• Support for RAID levels 0, 1, 3, 5, 0+1, 10, 30, 50 (10, 30, and 50 using host-based
software RAID)
• Support for multiple RAID sets, multiple hosts, and LUN masking and mapping
• Background RAID set creation; automatic variable background rebuilding5; online
expansion; LUN slicing; global drive hot sparing (per RAID controller)
Fibre Channel storage-to-host connection
• Dual 2Gb Fibre Channel ports (SFP); 200MB/s throughput per channel with guaranteed
bandwidth (400MB/s full duplex)3
• Host connectivity using 2Gb Apple Fibre Channel PCI Card (sold separately) or
compatible third-party PCI card
• Support for point-to-point, loop, and switched fabric topologies
• Dual 10/100BASE-T Ethernet interfaces for remote management
Apple Fibre Channel PCI Card (sold separately)
• 64-bit, 66MHz card with two SFP 2Gb Fibre Channel ports; compatible with 32-bit,
66MHz PCI slots and 64-bit, 100MHz or 133MHz PCI-X slots
• Two 2.9-meter Fibre Channel copper cables with embedded SFP transceivers;
compatible with SFP fiber-optic cables and transceivers
Cooling
• Redundant, hot-swappable cooling modules with self-regulating speeds and front-toback
cooling
• Environmental monitoring system for automatically maintaining optimal ambient
temperature
Technology Overview 27
Xserve RAID
Electrical
• Redundant, load-sharing hot-swappable power supplies (450W); universal input
(100V to 240V AC), power factor corrected
• Maximum input current: 7.6A (100V to 127V) or 3.6A (200V to 240V)
• Power usage: 300W typical continuous power, 400W maximum continuous power
• Dual DB-9 serial ports for UPS systems
• Frequency: 50Hz to 60Hz, single phase
Environmental requirements and approvals
• Operating temperature: 50° to 95° F (10° to 35° C)
• Storage temperature: –40° to 116° F (–40° to 47° C)
• Relative humidity: 5% to 95% noncondensing
• Maximum thermal output: 1365 BTUs per hour
• Maximum altitude: 10,000 feet
• FCC Class A approved
Size and weight
• Height: 5.25 inches (13.3 cm)
• Width: 17 inches (43.2 cm)
• Depth: 18.4 inches (46.7 cm)
• Fits EIA-310-D–compliant, industry-standard 19-inch-wide four-post racks from
24 to 36 inches deep; deeper racks require third-party extender
• 60 to 110 pounds (27 to 45 kg), depending on configuration
Technology Overview 28
Xserve RAID
1For hard drive capacity measurements, 1GB = 1 billion bytes and 1TB = 1 trillion bytes; actual formatted capacity less. Maximum
capacity of 3.5TB achieved through use of fourteen 250GB Apple Drive Modules. Usable capacity depends on drive configuration
and RAID level. 2See www.apple.com/xserve/raid for information on third-party certifications and qualifications. 3Actual rates will
vary depending on drive configuration and RAID level. 4Host operating system limitations apply. 5Automatic rebuild requires a designated
hot spare; not available for RAID level 0. 6Throughput based on testing performed by Apple in January 2004 using Iometer
(version 2003.05.10) sequential read tests with 4MB block size and 16 workers. Xserve RAID was configured with 14 drives and RAID
50; the host was a Power Mac G5 with 1GB SDRAM, Mac OS X Server v10.3.1, HFS+ (journaled) file system, and Apple Fibre Channel
PCI Card. 7A separate AppleCare Premium Service and Support Plan must be purchased for each Xserve RAID system to be covered.
To qualify, systems must be within the one-year hardware warranty. Coverage ends three years after date of Xserve RAID purchase.
Actual onsite response time and availability of onsite service depend on location; see www.apple.com/support/products/premium
for details. Support also covers Apple-qualified Xserve RAID solutions; see www.apple.com for a list of supported third-party solutions.
Local telephone fees may apply; telephone numbers may vary and are subject to change.
© 2004 Apple Computer, Inc. All rights reserved. Apple, the Apple logo, Apple Store, Mac, Macintosh, Mac OS, Power Mac, and Xserve
are trademarks of Apple Computer, Inc., registered in the U.S. and other countries. Rendezvous is a trademark of Apple Computer,
Inc. AppleCare is a service mark of Apple Computer, Inc., registered in the U.S. and other countries. Java and all Java-based trademarks
are trademarks or registered trademarks of Sun Microsystems, Inc. in the U.S. and other countries. PowerPC is a trademark
of International Business Machines Corporation, used under license therefrom. Other product and company names mentioned
herein may be trademarks of their respective companies. Product specifications are subject to change without notice. This material
is provided for information purposes only; Apple assumes no liability related to its use. January 2004 L301297A
For More Information
For more information about Xserve RAID
and other Apple server solutions, visit
www.apple.com/server.