StorGateTM
Storage Gateway
for VOS Continuum to Hitachi Connectivity
Fiber Model
Product Brief
The DRA StorgateTM
Storage Gateway drop-in solution provides VOS Continuum hosts with seamless
access to VOS data on Hitachi 99xx series storage arrays.
StorGate meets all requirements for a
certified host. By using StorGate, Stratus VOS Continuum users
can store and retrieve VOS data on their existing storage arrays while
maintaining full support for their equipment.
Key Features
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Provides drop-in fully supported
VOS-to-Hitachi connectivity
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Connects directly to Hitachi via Fibre Channel (FC-AL)
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Connects directly to VOS Continuum via
K480 fiber controller or JBOD disk enclosure
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Allows VOS to see Hitachi
storage as common VOS disk types (D913 and D914*)
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Emulates VOS disks and disk trays - up to
14 virtual VOS disks per StorGate/RAID unit
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Stores VOS data directly in VOS file format
(Note: VOS does not support data sharing between hosts)
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Can be duplexed to standard Stratus VOS
disks or can be used in pairs for duplexing
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Meets or exceeds native VOS
disk performance in most applications (using Hitachi mirroring
with metavolumes)
Subsystem Overview
StorGate provides
a connection between a VOS Continuum Fiber (K480) controller and
an Hitachi host adapter port. StorGate "on-the-fly" disk emulation and data
translation capabilities allow VOS Continuum users to store and retrieve data on
an Hitachi just as if the data were stored on standard
Stratus disks.
Each StorGate unit provides access to up to 14
virtual VOS disk volumes on the Hitachi. Each of these virtual disks may be any
supported VOS 9xx disk type. This means that each StorGate unit allows a VOS
Continuum to access up to 476 GB (physical) on an Hitachi storage array. Multiple
StorGate units may be attached
to multiple fiber ports on a single VOS Continuum host to provide access to as
much Hitachi storage capacity as desired, up to the maximum allowed by VOS. Multiple StorGate
units may also be used to allow multiple VOS Continuum hosts to access one or
more Hitachi storage arrays. (Although StorGate allows
multiple VOS hosts to store data on a single Hitachi, VOS limitations prevent
sharing that data between hosts.)
StorGate supports all VOS disk-related
commands and functions. It uses standard RAID hypers and metavolumes to
store VOS data on an Hitachi storage array. This allows the Hitachi to manage VOS virtual
disks as standard RAID storage volumes. Both mirrored and Raid-S volume types
are supported.
Physical Connections
A VOS Continuum host connects to
StorGate through a Continuum K480 fiber controller. an Hitachi storage array connects
to StorGate through a Fibre Channel port on the Hitachi Fibre Channel host adapter. (Refer
to the StorGate Technical Specifications for connection
details.)
Configuration Options
StorGate provides a variety of highly flexible
configuration options for access to the Hitachi from VOS Continuum
hosts. This flexibility arises from the unique way in which StorGate stores VOS data on the
Hitachi.
Performance
Laboratory tests indicate that for many
applications StorGate provides throughput which equals or exceeds that of
equivalent Stratus disks. In these laboratory tests the best performance was
achieved when the virtual disks on the Target storage array were configured as
Target-specific
mirrored metavolumes. Performance in other environments may vary, and
depends upon a variety of factors. These factors include application data access
patterns, overall Target storage array configuration, and I/O activity by other
hosts attached to the Target storage array.
Optional Feature: PowerPath
Facility
The
optional StorGate PowerPath Facility allows Stratus users to take advantage of
EMC’s PowerPath, a host-based software that works with the storage system to
intelligently manage I/O paths.
PowerPath supports multiple paths to a logical device, enabling the facility to
provide automatic failover in the event of a hardware failure. PowerPath
automatically detects path failure and redirects I/O to another path.
PowerPath also provides dynamic multi-path load balancing for many storage
platforms. It distributes I/O requests to a logical device across all
available paths, thus improving I/O performance and reducing management time and
downtime by eliminating the need to configure paths statically across logical
devices. Check with your EMC representative for support of load balancing
on your storage platform.
PowerPath Facility runs
automatically and without administration required. PowerPath is enabled
through a dual port fiber card as opposed to the single port fiber card that
comes standard with StorGate.
Product Support
DRA products purchased through Stratus
are supported jointly by DRA and Stratus. DRA products
purchased directly from DRA are supported through the Co-active Maintenance
Service (CMS). CMS is a total support agreement which is available "around
the clock, around the world" to participating DRA customers. Product
maintenance, product updates, documentation and training are available through
CMS support. CMS is provided free of charge for 90 days following product
installation, and may be extended by contract thereafter.
* VOS D913 and D914 disks are currently supported on StorGates. Stratus
no longer sells D913 disks, but the D913 disk type remains in VOS. Therefore,
StorGates can be configured as D913s. If StorGates are partnered to StorGates or
SuperSyncs, users may choose to use the D913 disk type, depending on their
capacity needs. However, for most users it will no longer be practical to
partner StorGates to Stratus D913 disks.
