Versatile Storage Server Overview
VSS is designed to offer several new features and benefits to satisfy customers
who require a central pool of storage. It is the first disk product to use the
Seascape architecture, (see Chapter 2, “Versatile Storage Server Architecture”
on page 21). The philosophy behind the architecture is that of common parts;
that is, to take parts and subsystems from other divisions within IBM and build
new products with them. The advantage to the customer is that the components
within the product are tried and tested and have a known high reliability. Using
existing components and subassemblies also helps to keep the cost down, as
there are reduced development costs and the benefits of large-scale
VSS is designed to meet both customer and storage infrastructure requirements;
see “Customer Requirements” on page 8 and “Storage Infrastructure
Requirements” on page 15.
VSS offers the customer:
A central pool of storage
Offers the ability to distribute the storage pool among up to 64
heterogeneous hosts and reassign the storage distribution as requirements
change. All activity can be carried out with the storage system online.
Allows assigning a storage partition to multiple hosts so that true data
sharing can take place. File locking and record-level locking are the
responsibility of the application program.
Chapter 1. Introduction 17
Provides an easy-to-use web-based browser interface, so that configuring
and maintaining the system is as simple as possible.
Offers built-in protection against data loss, and loss of data integrity.
Can maintain access to the data under almost all circumstances.
Through its “plug and play” I/O architecture, components can easily be
changed as technology changes without disruption. The ability to use
existing 7133 disk drawers and racks demonstrates IBMs commitment to
protecting customer investment in storage.
VSS uses existing RISC processor boards and chips, SSA disks and adapters,
racks and power supplies from ES/390 servers, coupled with the resource and
expertise of more than 40 years of making disk subsystems.
VSS consists of a high-performance storage server complex with 512 MB cache,
expandable to 6 GB, redundant power supplies, and one or more drawers of
high-performance SSA disks. The controller complex has built-in redundancy to
protect against possible failure. Data is always protected from disk failure by the
use of RAID-5. The capacity is highly scalable. The minimum configuration is
two drawers (32*9.1 GB disks) with two RAID arrays configured. The usable
storage capacity is 230 GB. The maximum number of disk drawers is 18. The
supported disk sizes are 4.5 GB and 9.1 GB. The total disk storage, using 9.1 GB
drives, is 2.62 TB with a usable capacity of 2.0 TB. (The usable capacity
calculation is 18 drawers * 13 drives * 8.77 GB per drive = 2.05 TB.)
VSS is designed for use in multihost, heterogeneous environments. Up to 64
hosts can be attached concurrently. Supported hosts are the RS/6000, RS/6000
SP, AS/400, Sun Ultra series, the HP 9000 800 series, some Data General models
and also PC support on various IBM and Compaq servers. Support for additional
hosts is planned to be announced in the coming months. Host attachment is by
the use of UltraSCSI adapters; this is backward compatible with SCSI-2D F/W.
The VSS presents a known disk image to the attached host. The AS/400 is
presented with the image of a 9337 disk subsystem while UNIX machines “see” a
generic SCSI disk. The disk image can be divided into LUNs.
VSS has two interface types, a web-based browser interface, known as the IBM
StorWatch Versatile Storage Specialist (VS Specialist for short), for user
configuration and control of the subsystem, and a serial attach interface for use
by service personnel. Additionally a modem connection for remote diagnostics
and download of fixes can be made.
A full description of the architecture and implementation is in Chapter 2,
“Versatile Storage Server Architecture” on page 21 and Chapter 4, “Versatile
Storage Server Data Flow” on page 109. VSS is positioned to complement
rather than replace existing IBM products. The typical VSS customer will have:
450+GB of storage attached to several different servers
Common location of servers
Common management and control or the desire to create them
For a business requiring storage of large amounts of data using a single host or
all RS/6000 hosts, other storage solutions should be considered. For the
homogeneous RS/6000 environment, native attached 7133 SSA disks should be
considered, especially for stand-alone servers, or small clusters. For UNIX
environments where a common storage pool is not required, 7133 SSA disks
18 IBM Versatile Storage Server
attached using the Vicom SLIC, IBM 7190, or IBM SSA adapter for Sun S-Bus
should be considered.
Chapter 1. Introduction 19
20 IBM Versatile Storage Server

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