IBM Versatile Storage Server

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

manufacture.

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 IBM′s 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