choosingt h e r i g h t R A I D s o l u t i o n f o r y o u r b u s i n e s s

f a u l t t o l e r a n c ea v a i l a b i l i t yh i g h p e r f o r m a n c ed a t a i n t e g r i t ys c a l a b i l i t ye a s e o f u s e

The Adaptec® Array Guide

p r i n t s e r v e r s

d a t a b a s e s

f i l e s e r v e r s

i n t e r n e t

c l u s t e r i n g

i m a g i n g

introductionBusinesses today are increasingly using network servers to create enterprise-wide information

technology solutions at a fraction of the cost of mainframe- or minicomputer-based solutions.

Unfortunately, many of these systems are not designed for business-critical applications. As a

result, disk drive failures can literally bring your business to a standstill — costing you thousands

of dollars per hour in lost sales, productivity, and goodwill.

Redundant Arrays of Inexpensive Disks (RAID) technology was developed to address the fault-

tolerance and performance limitations of conventional disk storage. While arrays were once considered

complex and relatively specialized storage solutions, today they are easy to use and essential for a

broad spectrum of client/server applications. This guide provides a highly understandable introduction

to RAID technology and its applications, and summarizes the range of array solutions Adaptec offers.

A longtime leader in high-performance, system-based bandwidth solutions, Adaptec has the

expertise and experience to help you choose the right array solution for your business. With our

flexible, expandable array solutions, you can match performance and cost to a specific set of

applications and easily grow over time — ensuring that you always have the high availability and

data integrity needed.

At Adaptec, we are committed to helping you choose the right RAID solution for your business

because in today’s competitive environment, all data is business-critical.

2

scalable

Table of Contents

Scalable Array Solutions   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .3

Understanding RAID   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .4

Building an Array Storage Subsystem   .  .  .  .  .  .  .  .  .  .  .8

Adaptec Array Solutions

AAA™-130 PCI Array Adapter Series   .  .  .  .  .  .  .  .  .  .10

ARO™-1130 PCI RAIDport™ Card   .  .  .  .  .  .  .  .  .  .  .  .11

AEC™-4312A/7312A External Array Controllers   .  .  .  .12

Adaptec CI/O™ Array Management Software   .  .  .  .  .  .  .13

Adaptec Quality and Reliability   .  .  .  .  .  .  .  .  .  .  .  .  .  .14

Glossary   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .14

Appendices   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .17

What is an array?

a r r a y s o l u t i o n s

Adaptec offers a broad selection of high-quality, highly-scalable array solutions that apply RAID technology tokeep businesses up and running. This wide range ofarray solutions ensures that users can obtain the exactprice/performance match to meet a variety of applicationand network requirements — from smaller networksrunning on entry-level servers to enterprise-wideapplications.

Equally important, Adaptec’s sophisticated, yet easy-to-use CI/O Array Management software is used for allour array solutions.* This gives businesses a common,user-friendly interface and seamless scalability, makingit easy to add capacity or reconfigure arrays as needed.

Today, our array family includes three product lines.First is the AAA-130 series, PCI array adapters that aredesigned for entry-level Intel-based servers running fileand print services, as well as small database applications.These array adapters deliver higher performance, morerobust fault tolerance, and are easier to use than embed-ded network operating system (NOS) RAID software— at a price consistent with an entry-level server’s coststructure.

3

An array is defined as two or more disks grouped together to appear as a single device to the host system. In common usage, the

term implies the use of some form of redundancy to increase overall data availability, data integrity, and

performance. There are several different RAID “levels” or redundancy schemes, each with charac-

teristics that make it suited to a specific set of applications or network requirements.

* Adaptec CI/O Array Management software will be supported in future releases of the AEC-4312A and AEC-7312A external array controllers.

RAIDNext, there’s the ARO-1130 PCI RAIDport card, ahigh-performance RAID upgrade card that provides anultra-affordable entry point to an array solution forentry-level servers. The ARO-1130 card uses a RAIDportconnector and embedded Adaptec SCSI ASICs in a servermotherboard to deliver the same benefits as the AAA-130series. The ARO-1130 card is available exclusively throughAdaptec original equipment manufacturers (OEMs).

Finally, the fully platform-independent AEC-4312Aand AEC-7312A high-performance external array con-trollers enable large-scale, fault-tolerant storage subsys-tems. These array controllers are optimized for midrangeand high-end Intel-based and entry-level UNIX-basedservers and workstations, as well as for clustered serverenvironments.

Our flexible solutions allow users to start with onearray solution — for example, one of the AAA-130 seriesof array adapters — and easily migrate to anotherAdaptec array solution, without reformatting, as needs

change over time.

What is RAID technology?

RAID technology was first defined by a group of computerscientists at the University of California at Berkeley in1987. The scientists studied the pos-sibility of using two or more disks toappear as a single device to the host system.

Although the array’s perfor-mance was better than that oflarge, single-disk storagesystems, reliability was unac-ceptably low. To address this, the scientistsproposed redundant architectures to provide waysof achieving storage fault tolerance. In addition todefining RAID levels 1 through 5, the scientists alsostudied data striping — a non-redundant array config-uration that distributes files across multiple disks in anarray. Often known as RAID 0, this configuration actu-ally provides no data protection. However, it does offermaximum throughput for some data-intensive applica-

tions such as desktop digital video production.No individual RAID level is inher-

ently superior to any other. Eachof the five array architectures iswell-suited for certain types ofapplications and computingenvironments. For client/server

applications, storage systemsbased on RAID levels 1,0/1, and 5 have been themost widely used. This isbecause popular NOSs

such as Windows NT®

4

u n d e r s t a n d i n g

Adaptec has a family of array solutions to match specific cost, performance, and availability requirements ofall Intel-based and entry-level UNIX-based servers. See Appendix A fortypes of server applications.

* Just a bunch of drives.

Server and NetWare manage data in ways similar tohow these RAID architectures perform.

The table in Appendix B summarizes the strengthsand weaknesses of each RAID level.

What does RAID provide?

RAID technology does not prevent drive failures.However, RAID does provide insurance against disk

drive failures by enabling real-timedata recovery without data loss.

The fault tolerance of arrays canalso be significantly enhanced bychoosing the right storage enclosure.Enclosures that feature redundant,hot-swappable drives, power sup-plies, and fans can greatly increasestorage subsystem uptime based on

a number of widely accepted measures: Mean Time toData Loss (MTDL), Mean Time of Data Availability(MTDA), Mean Time to Repair (MTTR), and MeanTime Between Failure (MTBF). For brief definitionsof these terms, please refer to the glossary.

The driving factors behind RAID

A number of factors are responsible for the growingadoption of arrays for critical network storage. Astoday’s applications create larger files, network stor-age needs have increased proportionately. To accom-modate expanding storage requirements, users areadding disk drives — raising the odds of drive failures.In addition, accelerating CPU speeds have outstrippeddata transfer rates to storage media, creating bottlenecksin today’s systems.

Arrays overcome these challenges by providing acombination of outstanding data availability, extraor-dinary and highly scalable performance, and highcapacity.

5

Data AData B

Par i ty C

Data APar i ty BData C

Par i ty AData BData C

RAID 0 — Data Striping(minimum 2 drives — no protection)

RAID 0/1 — Data Stripingand Mirroring (minimum 4 drives)

RAID 5 — Data Striping with Distributed Parity (minimum 3 drives)

Mirroring

Duplexing

Ó Each RAID level hasinherent cost, performance,and availability (fault-toler-ance) characteristicsdesigned to meet differentstorage needs. Most RAIDlevels can effectively sat-isfy only one or two ofthese criteria. RAID 5 isthe exception — providingthe best overall balanceof cost, performance, andavailability for mostservers.

StandardHost Adapter

StandardHost Adapter

StandardHost Adapter

RAID 1 — Mirroring andDuplexing (2 drives)

6

Outstanding availability

More and more organizations have created enterprise-wide networks to improve productivity and streamlineinformation flow. While the distributed data stored onnetwork servers provides substantial cost benefits, thesesavings can be quickly offset if information is frequentlylost or becomes inaccessible. RAID storage solutionsprovide critical reliability by enabling recovery with noloss of data or interruption of user access.

Scalable performance

While disk drive performance has risen steadily, it hasnot kept pace with the increase in CPU speeds. As aresult, I/O processing time and throughput are limitedby the capabilities of any single disk. Array solutionsprovide a greater range of performance scalability thanindividual drives as capacity is increased. In arrays, diskswork together to handle multiple I/O requests simulta-neously. Further, sustainable throughput can be improvedbecause disks can be written and read in parallel.

High capacity

By integrating multiple drives into a single array —which is viewed by the network operating system as asingle disk drive — organizations can create cost-effec-tive, minicomputersized solutions of up to a terabyte ormore of storage. This is much higher than the capacityof any single disk drive.

Types of arrays

There are three primary array implementations: software-based arrays, bus-based array adapters/controllers, andsubsystem-based external array controllers. As with the

various RAID levels, no one implementation is clearlybetter than another — although software-based arraysare rapidly losing favor as high-performance, low-costarray adapters become increasingly available. Each arraysolution meets different server and network requirements,depending on the number of users, applications, andstorage requirements.

It is important to note that all RAID code is based onsoftware. The difference among the solutions is wherethat software code is executed — on the host CPU (soft-ware-based arrays) or offloaded to an on-board processor(bus-based and external array controllers).Software-Based Arrays Primarily used with entry-levelservers, software-based arrays rely on a standard hostadapter and execute all I/O commands and mathemat-ically intensive RAID algorithms in the host server CPU.This can slow system performance by increasing hostPCI bus traffic, CPU utilization, and CPU interrupts.Some NOSs such as NetWare and Windows NT includeembedded RAID software. The chief advantage of thisembedded RAID software has been its lower cost com-pared to higher-priced RAID alternatives. However, thisadvantage is disappearing with the advent of lower-cost,bus-based array adapters such as the AAA-130 seriesand the ARO-1130 RAIDport card from Adaptec.Bus-Based Array Adapters/Controllers Unlike software-based arrays, bus-based array adapters/controllers pluginto a host bus slot [typically a 133 MByte (MB)/sec PCIbus] and offload some or all of the I/O commands andRAID operations to one or more secondary processors.Originally used only with mid- to high-end servers dueto cost, lower-cost bus-based array adapters are nowavailable specifically for entry-level server networkapplications (i.e., AAA-130 series from Adaptec).

Is duplexing effective?

Duplexing — which eliminates the host adapter as a single point of failure — is one of the most popular methods for increasing

fault tolerance under RAID 1 (mirroring). Used exclusively with low-performance, software-based RAID solutions, duplexing host

adapters alone unfortunately, offers no protection against the failure of other server or storage system components. For example,

the failure of power supplies and fans, which have relatively low MTBF ratings, can bring down a system more often than a host

adapter failure.

The concept behind RAID is relatively simple. The fundamental premise is to be able to recover

data on-line in the event of a disk failure by using a form of redundancy called parity. In its

simplest form, parity is an addition of all the drives used in an array. Recovery from a drive failure

is achieved by reading the remaining good data and checking it against parity data stored by the array. Parity is

used by RAID levels 2, 3, 4, and 5. RAID 1 does not use parity because all data is completely duplicated (mirrored). RAID 0,

used only to increase performance, offers no data redundancy at all.

Basics of simple parity

7

In addition to offering the fault-tolerant benefits ofRAID, bus-based array adapters/controllers performconnectivity functions that are similar to standard hostadapters. By residing directly on a host PCI bus, theyprovide the highest performance of all array types.Bus-based arrays also deliver more robust fault-tolerantfeatures than embedded NOS RAID software.

As newer, high-end technologies such as Fibre Channelbecome readily available, the performance advantageof bus-based arrays compared to external array controllersolutions may diminish.External Array Controllers Intelligent external arraycontrollers “bridge” between one or more server I/Ointerfaces and single- or multiple-device channels. Thesecontrollers feature an on-board microprocessor, whichprovides high performance and handles functions suchas executing RAID software code and supporting datacaching.

External array controllers — such as the AEC-4312Aand AEC-7312A array controllers from Adaptec — offercomplete operating system independence, the highestavailability, and the ability to scale storage to extraordi-narily large capacities (up to a terabyte and beyond).These controllers are usually installed in networks ofstand alone Intel-based and UNIX-based servers aswell as clustered server environments.

Software-based Array

Bus-based ArrayAdapter/Controller

External Storage Subsystem

ExternalArrayController

StandardHost Adapter

StandardHost Adapter

Adaptec array adapters and controllers are the corner-stones of a fault-tolerant storage solution. However,additional hardware components can greatly enhancethe reliability and data availability of an array. Thesecomponents include the storage enclosure, drives, ter-minators, and cables.

Storage enclosures

To create an array solution, userscan choose from two types ofstorage enclosures: internal orexternal (see right). Many entry-level, PCI-based servers nowinclude internal hot-swappabledrives for array applications.Both the AAA-130 series andthe OEM-offered ARO-1130RAIDport card are well-suitedfor these types of servers.

The second option is to buyan external array enclosure (seeAppendix C) and add drives.When choosing the enclosure, itis important to balance cost with the need for storagesystem reliability. Various features found in arrayenclosures — such as redundant, hot-swappable powersupplies and fans — can dramatically improve dataavailability, data integrity, and system serviceability.

Array enclosures also differ in the way they allowdrive replacement. Many server and storage manufacturersclaim to have array storage systems that have removable,hot-swap drive bays. Over the past few years, the term“hot swap” has been applied to everything from beingable to replace a drive while on-line and under-load tosimply permitting the system power to remain on whenadding or removing a drive. The latter feature is morecorrectly referred to as “warm swap.”

For true on-line, under-load, hot-swap functionality,users should select a server or an array enclosure thathas a SCSI backplane printed circuit board (PCB) orconnector on the drive tray with power and ground pins

8

buildinga n a r r a y s t o r a g es u b s y s t e m

An internal (within the server) RAID solution usuallyincorporates removable drives to provide an inexpensivecompact, real-time data recovery storage system.

In addition to increased storage capacity, an external RAIDsolution may provide non-stop features beyond the server’scapabilities, such as redundant power and cooling systems.

that are longer than the data pins. This design ensuresthat power will always be disconnected after the datapins are removed from the SCSI bus and vice-versa. Theresult is that no power spike “glitches” can occur on theactive SCSI bus, thereby avoiding data corruption orloss. For “warm-swap” enclosures, network managers

9

must see to it that all activity on the SCSI bus has ceasedbefore replacing a drive. To verify whether a particularserver or storage enclosure offers hot-swap support,check with the manufacturer.

Any Adaptec AAA-130 series adapter, ARO-1130RAIDport card, AEC-4312A controller, or AEC-7312Acontroller will provide an effective array solution whenchoosing an external storage subsystem. With a warm-swap enclosure, Adaptec’s CI/O Array Managementsoftware gives network managers the added flexibilityof pausing activity on the SCSI bus during drivereplacement, without affecting the NOS.

Disk drives

The choice of disk drives can greatly impact the overallperformance and capacity of array storage. Drives withrelatively high MTBFs and high RPM speeds will failless often and provide better performance than inferiordrives. Keep in mind that mixing drives of differentstorage capacities will limit the capacity of all drives inthe array to that of the lowest-capacity drive. This ensuresthat there is enough disk space available for redundancyinformation on all stored data. Appendix D provides alisting of some popular drive manufacturers.

In addition, many disk drives now include Self-Moni-toring, Analysis, and Reporting Technology (S.M.A.R.T.).These drives can be set up to report predicted failures,providing managers the opportunity to replace a drivebefore problems arise.

Adaptec array adapters and controllers supportmixing of different capacity drives within the samearray. However, Adaptec strongly recommends usingdrives with similar spindle speeds and capacities formaximum performance and capacity.

Termination and cabling

Proper termination and high-quality cables should alwaysbe used with SCSI devices, particularly when building anarray storage subsystem. When implementing Fast, Wide,or UltraSCSI technology, it is a good idea to use activeterminators and impedance-matched cables to avoidsignal reflections and data corruption. In addition, themaximum cable lengths outlined in the SCSI specificationshould be strictly followed.

Termination must be at the end of the cable or onthe storage enclosure’s backplane, not at the device.External array enclosures typically require an externalactive terminator that attaches to the SCSI connector onthe back of the enclosure. Appendix E provides a listingof SCSI cable kits available from Adaptec.

Both the AAA-130 series of array adapters andAEC-4312A* and AEC-7312A* array controllers areavailable in kits that include high-quality cabling andactive termination.

* Kits available in subsequent releases.

10

Clearly, there are many compelling reasons to employarray solutions. The challenge in the past has been to findthe right solution to get the required data availabilityand protection without paying a disproportionatelyhigh price or buying more of a solution than needed.

Adaptec’s high-performance, high-availability arraysolutions are designed to meet a broad spectrum ofbusiness requirements and effectively scale as needschange over time.

AAA-130 PCI array adapter series

Smaller businesses, departments, and workgroupssearching for a cost-effective RAID solution have oftenhad to settle for the mirroring/RAID software native toan NOS. The easy-to-use Adaptec AAA-130 series ofarray adapters provides a better, highly-affordablealternative that outperforms embedded NOS RAIDsoftware, while offering superior fault tolerance forenhanced data availability and data integrity.

The AAA-130 series improves performance overNOS RAID software through a combination of twoleading-edge hardware technologies (see above right).First, it creates a secondary on-board, 133 MB/sec PCIbus to offload and shield data traffic— such as disk reads/writes andRAID functions — from thehost’s main PCI bus. This uniquePCI-to-PCI bridge architecture is crit-ical because most entry-level, Intel-based servers have only one main PCI busthat supports three to four PCI slots. Add-in

adapteca r r a y s o l u t i o n sboards such as arrayadapters, host adapters,network cards, and videocards can greatly increasehost main PCI bus traffic.

Second, a separateRAID coprocessor with1 MB of memory boostsperformance by offloadingRAID 1 (mirroring) andRAID 5 write operationsfrom the server CPU. Withthe AAA-130 series ofadapters, the server CPU only has to pass data onceacross the main PCI bus. Then, the RAID coprocessorexecutes all RAID write operations on the board usingthe on-board PCI bus to talk directly with the disks inthe array. When the RAID write operations are com-pleted, a single interrupt is issued to the server CPU.

Beyond performance improvements, the AAA-130series enhances data availability by enabling hot swap-ping of drives in enclosures that are designed with thatcapability. It also supports hot sparing, which allowsusers to configure spare drives for automatic recoveryin the event of a failure — without having to manuallyswap drives. Further, because the AAA-130 seriesArrayConfig™ set-up utility makes it possible to bootsystems from a disk array, the NOS itself can be protected

from drive failure.AAA-130 adapters support both disk and

non-disk SCSI devices and are designed tomeet a variety of connectivity, per-

formance, and cost requirements. TheAAA-131 single-channel model is perfect

for systems with an installed add-in host adapter

AAA-131 Single-Channel PCI Array Adapter

The AAA-130series exceeds embed-ded NOS RAID software performanceby using an on-board RAID coprocessor andunique PCI-PCI bridge design.

AAA-130 adapters support both disk and non-disk SCSI devices and are designed to

meet a variety of connectivity, per-formance, and cost requirements. The

AAA-131 single-channel model is perfect for systems with an installed add-in host adapter

ARO-1130 PCI RAIDport card (OEM only)

Available exclusively from selected Adaptec OEM cus-tomers, the ARO-1130 PCI RAIDport card is a cost-effec-tive, high-performance array solution that delivers thesame features and benefits as the AAA-130 array adapterseries, but in a different implementation. The ARO-1130card upgrades embedded Adaptec SCSI channels and

connectors on a motherboard to SCSI RAIDchannels. OEMs can easily install a

RAIDport connector tomake a motherboard

with embedded Adaptec ASICsRAID-ready. Then, by pluggingin the ARO-1130 RAIDport card,

the motherboard is automatically upgraded from stan-dard SCSI to SCSI RAID. Using on-board SCSI controllersas RAID channels reduces the cost of the card, whileleveraging and preserving the investment in mother-board SCSI.

Once in place, the ARO-1130 RAIDport card providesbenefits that are similar to those delivered by the AAA-130series array adapters — making it an ultra-affordable,high-performance RAID solution for entry-level servers.For more information about the ARO-1130 RAIDportcard, or for a current list of OEMs contact Adaptec, or

visit Adaptec’s Web site at www.adaptec.com/RAID.

or embedded SCSI capabilities for low-speed tape andCD-ROM drives. However, if these slower-speed SCSIdevices are only accessed during off-peak hours, thenit is not necessary to connect the devices to a separatehost adapter — thus, further reducing system costs. TheAAA-133 adapter features three channels, enablingarrays to operate over multiple channels and allowingslower peripherals — such as CD-ROMs and tape drives— to communicate over their own, separatechannel. This multichannel feature also preservesvaluable PCI slots and reduces the need fora separate host adapter.

With the AAA-130 series, businesses cancreate up to four arrays in any combination ofRAID levels, including RAID 0, RAID 1, RAID0/1, and RAID 5. Up to 15 Fast/Wide SCSI or UltraSCSIdevices can be connected per channel. The AAA-130series is fully compatible with leading NOSs such asWindows NT, NetWare, OS/2 Warp,* SCO OpenServer,*and UnixWare.* This gives users more choices in systemsand peripherals, while protecting a business’ hardwareand software investment.

AAA-130 array adapters are supplied in a completehigh-value kit, including the array adapter with AdaptecArray1000™ Family Manager Set driver software, easy-to-use ArrayConfig initial boot array installation soft-ware, Adaptec CI/O Array Managementsoftware, 50- and 68-pin internal cableswith active termination, and complete doc-umentation. Simplified procedures makeinstallation fast and painless.

* Available in subsequent releases.

11

ARO-1130 RAIDport Card

PCI to SCSIASIC

RAIDportConnector

Host PCIBridge

HostCPU

Host MainPCI Bus

ARO-1130PCI RAIDport Card

AEC-4312A and AEC-7312A external array controllers

Adaptec’s AEC-4312A SCSI-to-SCSI and AEC-7312AFibre Channel-to-SCSI external array controllers are idealfor high-availability, high-capacity client/server appli-cations and clustered environments such as midrangeand high-end Intel-based servers, as well as entry-levelUNIX-based servers. Relying on a dual-channel WideUltraSCSI disk interface and a Wide UltraSCSI host

interface, the AEC-4312A con-troller delivers data transfer

rates of up to 40 MB/sec perchannel. The AEC-7312A

controller features ablazing 100 MB/secFibre Channel host

interface and a dual-channel Wide UltraSCSI

device interface.The two controllers offer a number of key benefits,

such as increased performance, outstanding fault toler-ance and scalability, easy field upgrade capability forinvestment protection, and simplified array configurationand management. Both the AEC-4312A and AEC-7312Acontrollers are fully operating system (OS) independent,connecting to any host without special OS drivers orsoftware. The controllers can support up to 30 externalhard disk drives, in up to four RAID arrays, to provideas much as 270 Gigabyte (GB) of RAID storage on a singlecontroller. Since each controller is presented as a singleSCSI ID to the host CPU, up to four controllers can beinstalled to deliver more than a terabyte (1000 GB) ofstorage capacity.

The performance advantages of the AEC-4312A andAEC-7312A controllers start with Adaptec’s high-perfor-mance PCI-to-PCI bridge architecture. Each controllerhas two independent, on-board PCI buses — one opti-mized for microprocessor activities, the other for data

transfers. This dual PCI bus design increases overallcontroller performance compared to controllers with asingle bus and memory, by allowing multiple opera-tions to be performed concurrently.

The controllers’ innovative design also takes fulladvantage of multiple on-board processors to maximizedata throughput by separately executing RAID commands,parity operations, and data caching. An on-board 133MHz 5x86 microprocessor — equivalent to a 75 MHzPentium — with its own memory subsystem makes quickwork of controller I/O commands. In addition, twopowerful on-board RAID coprocessors, supporting upto 32 MB of memory, accelerate performance by calcu-lating the mathematically intensive parity and cachingoperations independently. Performance can be furtherenhanced for specific applications by utilizing theAEC-4312A and AEC-7312A controllers’ advanced read-ahead, write-back, and write-through caching algorithms.

Both array controllers provide fault tolerance bysupporting RAID levels 0, 1, 0/1, 3,* 4,* and 5. Redun-dancy is also supplied through support for hot-swapdrives, hot sparing, ECC (error correction code)SIMMs, and battery backup of cached write-back data.For the highest data availability and performance,redundant controllers can be used to achieve active/active failover capability.*

Because host technologies tend to change more rapidlythan storage technologies, both the AEC-4312A andAEC-7312A array controllers feature field-upgradabledaughterboards. This designed-in upgrade path protectsan organization’s investment in controllers and storageby allowing simple, cost-effective migration to new hostinterface technologies as requirements change.**

* Support for RAID levels 3 and 4 and for active/active failover will be available in future releases.

** Subsequent releases of both controllers will also be available in a “cable-ready” canister for

easy installation into a standard drive bay of any external RAID storage enclosure.

12

AEC-7312A ExternalArray Controller

failures or additions tothe array configuration— as they happen acrossthe network. Reconfigu-ration of arrays is easy.Network managers sim-ply point and click at thenumber of drives desired.

Without leaving theirdesks, network personnel can use the software to:

• Determine if any drives have failed• Initialize arrays• Reactivate offline drives• Verify parity information• Blink individual drive lights or the lights of all

the drives in an array• Pause I/O to permit the removal of any drives

that aren’t hot-pluggable• Schedule management activities to be carried out

automatically any time of the day or night.In addition, disk drives equipped with S.M.A.R.T.

can be set up to report predicted failures, giving networkmanagers the opportunity to activate a spare drivebefore problems arise.

* Adaptec CI/O Array Management software will be supported in future releases of the

AEC-4312A and AEC-7312A external array controllers.

13

Arrays provide powerful solutions delivering high avail-ability and data integrity for today’s business-criticalapplications. Unfortunately, the complexity of currentarray solutions can create difficult manageability chal-lenges for network managers.

Adaptec CI/O Array Management software is theinterface to all Adaptec array solutions,* simplifyingarray management and providing seamless scalabilitythrough a built-in upgrade path.

With Adaptec’s CI/O Array Management software,network managers can monitor and manage storageeither locally or remotely from any PC or workstation onthe network. In Windows® operating systems, informationis presented in an easy-to-use graphical user interface.

The management software allows network managersto see at-a-glance both physical and logical array config-urations and other SCSI peripherals for any server usingAdaptec array adapters and controllers. Alerts, color-coded by their severity, keepnetwork personnelinformed about allevents — such as drive

ci/oa d a p t e c

a r r a y m a n a g e m e n ts o f t w a r e

Adaptec CI/O Array Management software provides an easy-to-use graphical interface for creating, managing,and monitoring Adaptec array solutions from across the building, the country, or around the world.

Windows NT Server

NetWare Server

Windows NT, 95, 3.11 Workstation

Windows NT, 95, 3.11 Workstation

Windows NT, 95, 3.11 Workstation

• Pick and click to reconfigure arrays• Zero-in on individual servers and arrays• Keep track of everything that happens

secondary controller comes on-line and takes over for the entiresystem. Active-passive arraycontrollers do not provide anyperformance benefit, only redun-dancy (fault tolerance). See alsoactive–active array controllers.

Array Two or more disks groupedtogether to appear as a singledisk to the host system.

Array adapter A bus-based(usually PCI) hardware device— such as an add-in card, groupof motherboard ASICs, or acombination of both — that con-verts the timing and protocol ofa host’s memory bus and an I/Obus. Usually used in entry-levelservers, an array adapter alsoincludes an on-board RAID co-processor to offload most of theRAID operations — for example,secondary RAID 1 writes andRAID 5 parity calculations —from the host CPU. This is incontrast to the microprocessor-based array controllers used inmidrange and high-end servers,which also offload I/O com-mands. Array adapters improveperformance over software RAIDsolutions embedded within net-work operating systems such asNetWare and Windows NT. Theseadapters provide the same con-nectivity functions as a standardhost adapter.

Bootable array An array whichincludes system disk files andallows a server to boot from thearray while protecting the net-work operating system disk —and other data on the array —from drive failure.

AAA - Adaptec Array Adapter Forexample, the AAA-130 arrayadapter series.

AEC - Adaptec External ControllerFor example, the AEC-4312Aand AEC-7312A external arraycontrollers.

ARO - Adaptec RAID Option Forexample, the ARO-1130 PCIRAIDport card.

ASIC - Application SpecificIntegrated Circuit Often used inthe context of motherboardembedded SCSI host adapters.See also Embedded SCSI ASIC.

Active–active array controllersMultiple external array controllers,each independently accessingstorage devices to provide faulttolerance and improved perfor-mance. In the unlikely event of acontroller failure, the remainingcontroller is able to provide unin-terrupted access to the entire datastorage subsystem. Active con-trollers offer redundancy as wellas nearly twice the performanceof a single controller (includingactive–passive controllers)because each one can access dataindependently. See also active–passive array controllers.

Active–passive array controllersProvides external array controllerfailover functionality similar tothat of a hot-spare drive (or otherredundant component). An active-passive array controller is poweredup (but not used) and waiting totake over the tasks of the primarycontroller in the event of a failure.If the primary controller fails, the

glossary

14

qualityAdaptec array solutions are backed by the same com-mitment to quality and reliability that has made Adaptecthe recognized leader in high-performance systembandwidth solutions for many years.

Trusted for quality and reliability, all Adaptec arrayadapters and controllers must pass comprehensivefunctional and mechanical tests in two separate labora-tories: the Adaptec Product Test Lab and the AdaptecCompatibility Test Lab. Adaptec has also earned thecoveted ISO-9002 international quality certification, adistinction that ensures the highest level of quality inproduct design and production. Adaptec products areincorporated into the products of nearly all major com-puter and peripheral manufacturers around the world.

In addition, the company’s products are designedto be compatible with a wide variety of hardware andsoftware configurations, for lasting investment protection.

The result is array solutions that users can count onto deliver exceptional availability, data integrity, andperformance for their business.

c o u n t o n a d a p t e c f o r

a n d r e l i a b i l i t y

15

CI/O - Comprehensive Input/Output Refers to Adaptec’s CI/OArray Management Software.

Clustering The concept of usingindependent computer systemsworking together as a singlelogical system. Clustering isusually implemented to addressboth availability and scalability.

Cold swap Power must beswitched off before the removalor insertion of a component.

Disk array See Array.

Disk/data striping Spreadingdata evenly over multiple disksto enhance performance. Some-times referred to as RAID 0, datastriping actually has no redun-dancy scheme and, therefore, doesnot provide any fault tolerance(data protection).

Downtime A time interval whena network cannot be used dueto equipment failure or anothercause.

Drive Synonym for disk, harddrive, hard disk, disk drive.

Duplexing Mirroring across twohost adapters. Used only withsoftware-based RAID storagesystems (usually the embeddednetwork operating system RAIDsoftware such as NetWare andWindows NT).

ECC (Error Correction Code)Refers to parity error detectionand correction within memoryor cache (for example, SIMM).Depending on the ECC SIMM,single-bit or double-bit parityerrors can be detected but notcorrected, or detected and cor-rected automatically.

Embedded SCSI ASIC (hostadapter) A “chip” that is attacheddirectly to the host motherboardand performs the same functionsas a standard add-in host adapter.

Exclusive OR (XOR) A processbased on a mathematical algo-rithm that is used by RAID levels2, 3, 4, and 5 to compare computerdata (binary 0s and 1s) createdby a write request or by a readrequest during a drive failure.The result of the XOR process isparity information that will bestored along with data for real-time recovery in the event of adisk failure.

External array controller In con-trast to bus-based array adaptersand microprocessor-based arraycontrollers, external array con-trollers reside in the externalRAID storage enclosure. Theyconnect to the host through astandard SCSI or serial (such asFibre Channel) host adapterinterface. These external con-trollers are similar to bus-based,microprocessor-based array con-trollers, in that they include anon-board microprocessor tooffload all RAID functions (I/Ocommands and RAID operations)from the host CPU. They areusually used in midrange andhigh-end servers — especiallyin clustering environments.

Failed-drive mode A mode ofreduced-performance operationthat a disk array is in after adrive failure.

Failover The automatic replace-ment of a failed system compo-nent with a properly functioningone. Most often used in the con-

text of redundant external arraycontrollers. If one of the con-trollers fails, failover enables thesecond controller to take overthe failed controller’s I/O load.See also active–active array con-trollers and active–passive arraycontrollers.

Fault tolerance The ability of asystem to continue to performits functions, even when one ormore components have failed.

Fibre Channel High-speed, serialinterface capable of supportingup to 100 MB/sec.

Host adapter A bus-based (PCI,EISA, ISA) hardware device, suchas an add-in card or ASIC, thatconverts the timing and protocolof a host’s memory bus and anI/O bus. See also embedded SCSIASIC and array adapter.

Hot spare RAID storage featurethat allows a spare drive (or othercomponent) to be configured forautomatic (in contrast to hot-swap)replacement and reconstructionin the event of a disk failure.Users can remain on-line andcontinue to access data. Also seehot swap and warm swap.

Hot swap A storage system’sability to allow the removal andreplacement of a disk drive (orother component) while usersare on-line and accessing data.In contrast to hot spare, this is amanual operation. Hot swaprequires that the storage (orserver) enclosure drive tray con-nectors be designed so that whena drive is removed, power is dis-connected before the groundconnection, and that the groundis restored before the power isreconnected upon reinsertion ofthe drive. This is usually accom-

plished by making the groundpin(s) in the drive tray connectorslightly longer than the data pins.See also hot spare and warm swap.

I/O - Input/Output Refers to net-work user data requests and hostoverhead such as swapping andfile system activity.

JBOD Just a bunch of drives.Refers to an array of drives with-out data redundancy.

MTBF Mean time between failure.Used to measure computer com-ponent average reliability/lifeexpectancy. MTBF is not as well-suited for measuring the reliabilityof array storage systems as MTDL,MTTR or MTDA (see below)because it does not account foran array’s ability to recover froma drive failure. In addition,enhanced enclosure environmentsused with arrays to increaseuptime can further limit theapplicability of MTBF ratingsfor array solutions.

MTDA Mean time between dataaccess (or availability). Theaverage time before non-redun-dant components fail, causingdata inaccessibility without lossor corruption.

MTDL Mean time to data loss. Theaverage time before the failureof an array component causesdata to be lost or corrupted.

MTTR Mean time to repair. Theaverage time required to bringan array storage subsystem backto full fault tolerance.

Member (disk) A disk that is inuse as a member of a disk array.

16

Microprocessor-based arraycontroller In contrast to anarray adapter, a microprocessor-based array controller includesan on-board microprocessor (forexample, an Intel i960) to offloadI/O commands and RAID oper-ations from the host CPU. Usuallyused in midrange and high-endservers. See also array adapter.

Mirroring Also known as RAID 1or duplexing (when using twohost bus adapters). Full redun-dancy is obtained by duplicatingall data from a primary disk ona secondary disk. The overheadof requiring 100 percent dataduplication can get costly whenusing more than two drives.

NOS - Network Operating SystemFor example, NetWare, WindowsNT Server, OS/2, SCO, andUnixWare.

PCI - Peripheral ComponentInterconnect Industry-standardspecification that refers to ahigh-speed (133 MB/sec) hostbus commonly used for hostadapters, Ethernet adapters, andvideo cards.

Parity A form of data redundancyused by RAID levels 2, 3, 4, and5 to recreate the data of a faileddrive in a disk array.

RAID Redundant array of inex-pensive disks. The term coinedin 1987 by researchers at theUniversity of California atBerkeley to describe a series ofredundant architectures used infault-tolerant disk arrays.

RAID Advisory Board (RAB)Industry organization of manu-facturers and users of disk systemsand related products whose mis-sion is to educate users regardingall aspects of storage technology,and in particular, RAID technology.

RAID levels Numbered 0 through5, RAID levels refer to differentarray architectures that offervarious advantages in terms ofdata availability, cost, and per-formance.

Read-ahead cache A performancecaching technique in which datais anticipated and read into thecache before it is actuallyrequested. See also write-backcache and write-through cache.

Redundant A duplicate disk orcomponent that provides arecovery path in case of a failure.

SCSI Small computer systeminterface (pronounced scuzzy).The fast, intelligent input/outputparallel bus used by high-perfor-mance peripherals.

SIMM Single in-line memorymodule.

SLED Single large expensive disk.Refers to older mainframe harddisks that were used as a basisfor comparison during the ini-tial UC Berkeley RAID studies.

S.M.A.R.T. - Self-Monitoring,Analysis and ReportingTechnology Drives equippedwith this feature report predictedfailures based on threshold valuesdetermined by the manufacturer.This allows the network managerto replace a drive before it fails.

management software) to main-tain data integrity during removalor replacement. Typically usedwhen hot swap is not supportedby the server or storage enclosuredrive tray. See also hot spare andhot swap.

Write-back cache A performancecaching technique in which thecompletion of a write request issignaled as soon as the data is incache; Actual writing to the diskoccurs at a later time. Since theoperating system is “fooled” intothinking that the write has actuallybeen written to disk, there is arisk of losing or corrupting datain cache should an error or powerfailure occur. Therefore, use of abattery-backed cache is recom-mended to prevent such data loss/corruption. See also read-aheadcache and write-through cache.

Write-through cache A cachingtechnique in which the completionof a write request is not signaleduntil data is safely stored on disk.Performance of write-through isessentially the same as in non-cached systems. See also read-ahead cache and write-back cache.

Software-based array An arrayin which all management func-tions including parity calculation(XOR) are performed by the hostserver CPU. These products arelow priced but have high CPUutilization and limited fault-tol-erant features. High-performance,low-cost array adapters arequickly replacing these inferiorsoftware-based arrays.

System disk The disk (or array)on which a system’s operatingsystem is stored and from whichit is initially loaded into systemmemory. See also bootable array.

Usable storage capacity Diskarray capacity that is usable fordata storage (vs. for mirroring orparity data). For example, undermirroring (RAID 1 and 0/1),usable storage remains a constantfifty percent (half of storage isalways used for redundancy).This is in contrast to other RAIDlevels such as RAID 5, in whichusable storage capacity is deter-mined by the formula of “n-1”.“n” is the total number of diskdrives and “1” is the number ofdisks worth of capacity used forparity (redundancy) overhead.So, as the number of disks in thearray grows, the usable storagecapacity percentage increases inrelation to parity (redundancy)information.

Warm swap The ability to removeand replace a disk drive whilethe power is on. All bus activitymust be paused (usually donethrough a utility within the array

17

appendix a

Matching Server Type and Applicationwith Adaptec Array Solutions

Server Type Ideal Applications

Adaptec has a scalable family of array solutions to match specific server types and their ideal application.

AAA-130Series

ARO-1130RAIDport Card

AEC-4312A AEC-7312A

Adaptec Array Solutions

✓ ✓

✓ ✓

✓ ✓

• Small company enterprise• Large company workgroup/department• File and print services• Small databases• Internet/intranet

• Medium-large company enterprise• Medium-large databases• File and print services• Clustered servers• Video servers• Internet/intranet

• Large company enterprise• Large databases• Clustered servers• Video servers• File and print services• Internet/intranet

Entry-level• up to 75 active users• up to 5 disks• 1 or 2 CPUs• up to $5K+

Midrange• up to 500+ active users• up to 15 disks• 2 or 4 CPUs• up to $15K+

High-end/Entry-level UNIX-based• up to 1000+ active users• > 15 disks• 4 CPUs• up to $25K+

%%

%

18

Comparing RAID Levels

appendix b

RAID Level Minimum Number Description Strengths Weaknessesof Drives

RAID 0 2 Data striping without Highest performance No data protection;redundancy One drive fails, all data is lost

RAID 1 2 Disk mirroring Very high performance; High redundancy cost overhead;Very high data protection; Because all data is duplicated, twice the Very minimal penalty on write storage capacity is requiredperformance

RAID 2 Not used in LAN No practical use Previously used for RAM error No practical use; environments correction (known as Hamming Same performance can be achieved by

Code ) and in disk drives before RAID 3 at lower costthe use of embedded error correction

RAID 3 3 Byte-level data striping Excellent performance for large, Not well-suited for transaction-oriented with dedicated parity sequential data requests network applications;drive Single parity drive does not support

multiple, simultaneous read and write requests

RAID 4 3 (Not widely used) Block-level data striping Data striping supports multiple Write requests suffer from same single parity-with dedicated parity simultaneous read requests drive bottleneck as RAID 3;drive RAID 5 offers equal data protection and better

performance at same cost

RAID 5 3 Block-level data striping Best cost/performance for Write performance is slower than RAID 0 with distributed parity transaction-oriented networks; or RAID 1

Very high performance, very high data protection; Supports multiple simultaneous reads and writes; Can also be optimized for large,sequential requests

RAID 0/1 4 Combination of RAID 0 Highest performance, highest data High redundancy cost overhead; (data striping) and protection (can tolerate multiple Because all data is duplicated, twice the RAID 1 (mirroring) drive failures) storage capacity is required;

Requires minimum of four drives

Each RAID level has strengths and weaknesses. RAID 1, 5, and 0/1 are the most widely-used for transaction-based network server applications. RAID levels 0and 3 are more commonly used in single-user environments like CAD/CAM or desktop digital video applications.

19

Partial Listing of Array (RAID)Storage Enclosure Manufacturers

JMR Electronics, Inc.20400 Plummer StreetChatsworth, CA 91311USATel: (818) 993-4801Fax: (818) 993-9173Internet: www.jmr.com

Kingston Technology Corp.17600 Newhope StreetFountain Valley, CA 92708USATel (U.S.): (800) 435-0642Fax (U.S.): (714) 438-1847Tel (Intl): (714) 437-3334Fax (Intl): (714) 438-1820Internet: www.kingston.com

Trimm Technologies350 Pilot RoadLas Vegas, NV 89119USATel: (800) 423-2024Fax: (702) 361-6067Internet: www.trimm.com

appendix c

20

Partial Listing of SCSI Disk DriveManufacturers

Fujitsu Computer Products ofAmerica, Inc.2904 Orchard ParkwaySan Jose, CA 95134-2009USATel (U.S.): (800) 626-4686Tel (Intl): (408) 432-6333Internet: www.fujitsu.com

IBM (International BusinessMachines) Corp.1 Old Orchard RoadArmonk, NY 10504USATel: (914) 765-1900Internet: www.ibm.com

Quantum Corp.500 McCarthy BoulevardMilpitas, CA 95035USATel: (800) 624-5545Internet: www.quantum.com

Seagate Technology, Inc.920 Disc DriveScotts Valley, CA 95066USATel: (408) 438-6550Fax: (408) 429-6356Internet: www.seagate.com

appendix d

21

Cables and Terminators from Adaptec

To Order Cables:Adaptec, Inc. (USA and Canada)Tel: (800) 442-7274, or

(408) 957-7274

Adaptec EuropeTel: 32 11 300 379

appendix e

AdaptecCable Part #

Internal CablesACK-F2F-5IT

ACK-W2W-5IT

External CablesACK-H2L

ACK-W2W-E

Converter CablesACK-GCH2L

ACK-68P-50P-E

ACK-68I-68E

ACK-50I-50E

CableType

Standard 50-pin internal SCSI ribbon cable with active termination — supports up to four 8-bitdevices.

High-density internal Wide (68-pin) cable with active termination — supports up to four 16-bit diskdrives.

External 50-pin low-density to 50-pin high-density (also called SCSI-2) cable.

High-density external Wide (68-pin) SCSI cable shielded with 68-pin male connector at both ends.Cable provides a screw attachment for a more secure connection.

This device connects low-density external cables to SCSI host adapters with 50-pin high-densityconnectors.

Fully electrically terminated external adapter to convert an external 68-pin connector to 50-pin connec-tor. Attaches Fast SCSI devices to a Wide SCSI connector. Cable provides a screw attachment for amore secure connection.

68-pin internal to 68-pin external converter cable. Allows users to port an internal SCSI connector to anexternal vacant slot in a PC. This enables users to utilize an internal connection to attach externalperipherals including disk arrays.

50-pin internal to 50-pin external converter cable. Allows users to port an internal SCSI connector to anexternal vacant slot in a PC. This enables users to utilize an internal connection to attach externalperipherals including disk arrays.

CableLength

5 ft.

1 meter(approx. 3 ft.)

3 ft.

1 meter(approx. 3 ft.)

Not applicable

Not applicable

15 in.

15 in.

These high-quality SCSI cable kits are certified and guaranteed by Adaptec. High-quality cables help reduce cable-related problems.

Adaptec Array Solutions:Major Features

22

Features

Array solution type

Ideal server type

Host interface

Device interface

SCSI, Fast/Wide SCSI, Ultra SCSI, Wide Ultra SCSI support

Number of SCSI channels

Both 50-pin and 68-pin connectors on internal channels

Disk and non-disk support

On-board RAID coprocessor

Multiple operating system support

Data striping (RAID 0)

Mirroring (RAID 1)

Data striping with distributed parity (RAID 5)

Hot-swap drive support

Hot-spare drive support

ArrayConfig initial boot array installation software

Array1000 Family Manager Set software

Adaptec CI/O Array Management software

AAA-131

Bus-based

Entry-level

PCI

SCSI

YES

1

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

AAA-133

Bus-based

Entry-level

PCI

SCSI

YES

3

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

ARO-1130PCI RAIDportCard

Bus-based

Entry-level

PCI

SCSI

YES

#

#

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

AEC-4312AExternal ArrayController

External

Midrange and High-end

SCSI

SCSI

YES

2

Not applicable

YES

YES

YES

YES

YES

YES

YES

YES

YES

OS independent, not needed

##

AEC-7312AExternal ArrayController

External

Midrange and High-end

Fibre Channel

SCSI

YES

2

Not applicable

YES

YES

YES

YES

YES

YES

YES

YES

YES

OS independent, not needed

##

AAA-130 PCI Array Adapter Series

# motherboard dependent## available in subsequent releases

The Adaptec family of array solutions have different hardware implementations to meet specific server/network requirements, but share many of the same advanced features.

appendix f

R

Copyright 1997 Adaptec, Inc. All rights reserved. Adaptec, the Adaptec logo and tagline,Adaptec CI/O, AAA, AEC, ARO, Array1000, ArrayConfig, and RAIDport are trademarks ofAdaptec, Inc., which may be registered in some jurisdictions. Windows and Windows NT areregistered trademarks of Microsoft Corporation, used under license. All other trademarks usedare owned by their respective owners.

Information supplied by Adaptec, Inc., is believed to be accurate and reliable at the time ofprinting, but Adaptec, Inc., assumes no responsibility for any errors that may appear in thisdocument. Adaptec, Inc., reserves the right, without notice, to make changes in product designor specifications. Information is subject to change without notice.

P/N 950062-011 7/97 Printed in U.S.A.

Adaptec, Inc.

691 South Milpitas Boulevard

Milpitas, California 95035

Tel: (408) 945-8600

Fax: (408) 262-2533

Adaptec Asia — Singapore

Tel: (65) 278-7300

Fax: (65) 273-0163

Adaptec Europe — Belgium

Tel: (32) 2-352-34-11

Fax: (32) 2-352-34-00

Adaptec Japan — Tokyo

Tel: (81) 3-5365-6700

Fax: (81) 3-5365-6950

Additional Sales Offices

France

Tel: (33) 1-3452-3434

Fax: (33) 1-3452-3432

Germany

Tel: (49) 89-4564060

Fax: (49) 89-45640615

United Kingdom

Tel: (44) 1276-854500

Fax: (44) 1276-854505

Latin America (Miami)

Tel: (305) 265-0399

Fax: (305) 265-1387

Literature:

1-800-934-2766 (USA and

Canada) or (510) 732-3829

Pre-sales Support:

1-800-442-7274 (USA and

Canada) or (408) 957-7274

Interactive Fax:

(408) 957-7150

World Wide Web:

www.adaptec.com/RAID

Internet ftp server:

ftp.adaptec.com

Adaptec USA Bulletin

Board Service (BBS):

(408) 945-7727

(up to 28,800 bps, using 8 bits,

1 stop bit, no parity)