Specifications
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Technology Overview
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 exibility over that of 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, short- and long-haul SFP transceivers, and ber-optic
cables, and work with industry-standard Fibre Channel switches.
400MB/s throughput
Each 2Gb Fibre Channel port oers 200MB/s bandwidth for a total throughput of up
to 400MB/s.
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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 2Gb or 4Gb Fibre Channel PCI cards in the host computer via
a thin, exible copper or ber-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 cards accept short-
and long-haul SFP transceivers, allowing use with ber-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 compo-
nents are eld-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 noties 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
notications as needed. If an environment manager fails, the other one takes charge
of monitoring the system.
Apple Fibre Channel PCI cards
Xserve RAID connects to an Xserve, Mac Pro,
or Power Mac host system using Apple dual- or
quad-channel 2Gb or 4Gb Fibre Channel PCI
cards (sold separately). Two or four 2.9-meter
copper cables are included with the card for
connecting to the two RAID controllers in the
Xserve RAID system.