Compaq 179740-001 - ProLiant - 3000 Guida di riferimento rapido

WHITEPAPER

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ECG073/0398

[March 1998]

Prepared By

Windows NT

Integration Team

Compaq Computer

Corporation

CONTENTS

Executive Summary 3

PCI Architecture 3

PCI Load Balancing 5

Performance Optimization

Using PCI Bus Balancing 5

Bus Balancing Rules 5

Example Configurations 6

PCI Bus Loading with

PCI Hot Plug 7

PCI Bus

Balancing Tools 9

System Management

Performance Monitor 10

Balancing Bus Use 10

PCI Bus Loading with

Redundant Controllers 10

Online Storage Controller

Recovery Option 10

Compaq Advanced Network

Control Utility 10

Future PCI Bus Loading

and Technical Summary 11

PCI Bus Balancing and Optimization on

Compaq ProLiant Servers

With the introduction of dual-peer PCI (Peripheral Component Interconnect) bus

architecture, Compaq recommends balancing the load between the two PCI buses to

achieve optimal performance on the server.

This white paper identifies the importance of PCI Bus Balancing and provides technical

configurations for achieving high performance and availability on bridged PCI buses

and dual-peer PCI bus architectures.

Additional Resources include:

PCI Bus Numbering in a Microsoft Windows NT



Environment, First Edition,

February, 1998 – Doc ID ECG024/0298.

Configuring the Compaq



ProLiant 5000 Server for Peak Performance, Fourth Edition,

July 1997 – Doc ID 679A/0697.

Implementing Online Storage Controller Recovery Option Under Windows NT



, July

1997 - Doc ID ECG066A/0797.

Compaq Advanced Network Error Correction Support using PCI Hot Plug with

Microsoft Windows NT



, August 1997 – Doc ID ECG057/0897.

Compaq Advanced Network Error Correction Support in a Microsoft

Windows NT



Server Environment, June 1996 – Part Number 353A/0696.

Advanced Network Fault Detection and Correction Feature for NetWare



, June 1996 –

Part Number 385A/0696.

WHITE PAPER (cont.)

ECG073/0398

NOTICE

The information in this publication is subject to change without notice.

COMPAQ COMPUTER CORPORATION SHALL NOT BE LIABLE FOR TECHNICAL

OR EDITORIAL ERRORS OR OMISSIONS CONTAINED HEREIN, NOR FOR

INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING FROM THE

FURNISHING, PERFORMANCE, OR USE OF THIS MATERIAL.

This publication does not constitute an endorsement of the product or products that were tested.

The configuration or configurations tested or described may or may not be the only available

solution. This test is not a determination of product quality or correctness, nor does it ensure

compliance with any federal, state or local requirements. Compaq does not warrant products

other than its own strictly as stated in Compaq product warranties.

Product names mentioned herein may be trademarks and/or registered trademarks of their

respective companies.

Compaq, Contura, Deskpro, Fastart, Compaq Insight Manager, LTE, PageMarq, Systempro,

Systempro/LT, ProLiant, TwinTray, ROMPaq, LicensePaq, QVision, SLT, ProLinea, SmartStart,

NetFlex, DirectPlus, QuickFind, RemotePaq, BackPaq, TechPaq, SpeedPaq, QuickBack, PaqFax,

Presario, SilentCool, CompaqCare (design), Aero, SmartStation, MiniStation, and PaqRap,

registered United States Patent and Trademark Office.

Netelligent, Armada, Cruiser, Concerto, QuickChoice, ProSignia, Systempro/XL, Net1, LTE

Elite, Vocalyst, PageMate, SoftPaq, FirstPaq, SolutionPaq, EasyPoint, EZ Help, MaxLight,

MultiLock, QuickBlank, QuickLock, UltraView, Innovate logo, Wonder Tools logo in black/white

and color, and Compaq PC Card Solution logo are trademarks and/or service marks of Compaq

Computer Corporation.

Other product names mentioned herein may be trademarks and/or registered trademarks of their

respective companies.

Microsoft, Windows, Windows NT, Windows NT Server and Workstation, Microsoft SQL Server

for Windows NT are trademarks and/or registered trademarks of Microsoft Corporation.

PCI Bus Balancing and Optimization on Compaq

ProLiant Servers

First Edition (March 1998)

Document Number: ECG073/0398

WHITE PAPER (cont.)

ECG073/0398

EXECUTIVE SUMMARY

With the introduction of the Compaq ProLiant 5000 Server and its dual-peer PCI (Peripheral

Component Interconnect) bus architecture, Compaq recommended certain configurations to

balance the load between the two PCI buses and achieve optimal performance on the server.

Customers now question what load balancing means, how it affects server performance and what

to consider for future planning and implementation of PCI bus loading.

This white paper identifies the overall importance of PCI bus balancing and provides technical

configurations for achieving high performance and availability on bridged and dual-peer PCI bus

architectures. The supporting facts presented along with recommendations will assist system

administrators and network operators in attaining and maintaining this goal.

PCI ARCHITECTURE

Two basic architectures are used to connect the primary and secondary PCI bus to the host bus:

the dual-peer PCI bus or the bridged PCI bus. The dual-peer bus architecture, as shown in

Figure 1, provides two PCI buses independently linked to the host processor bus by means of two

Host-to-PCI Bridges. Since each PCI bus runs independently, it is possible to have two PCI bus

masters transferring data simultaneously thus producing more overall throughput. This is an

advantage with systems that have two or more high-bandwidth peripherals. Splitting these

peripherals between the two buses provides an uniformed load.

Slots

Host Bus

Memory

Secondary PCI Bus

Host-

to-PCI

PCI-to-EISA

EISA Bus

33 MB/s

133 MB/s 133 MB/s

Primary PCI Bus

540 MB/s

Bridge Bridge

Bridge

Slots

Processors

Figure 1: Dual-peer PCI architecture.

The bridged PCI architecture, as shown in Figure 2, requires all processed transactions on the

bridged PCI bus (the secondary bus) to go through the PCI-to-PCI Bridge to reach the primary

bus, then through the Host-to-PCI Bridge. In effect there is only one path to the host bus;

therefore, no load balancing is required on a system with this type of architecture.

NOTE: Table 1 lists the

Compaq ProLiant family of

servers that embody the

dual-peer PCI bus architecture.

NOTE: Table 1 lists the

Compaq ProLiant family of

servers that embody the bridged

PCI bus architecture.

WHITE PAPER (cont.)

ECG073/0398

PCI-to-PCI

Bridge

Processors Memory

Host Bus

Host-to-PCI

Bridge

PCI Bus

133 MB/s

PCI Bus 133 MB/s

Slots

Figure 2: Bridged PCI architecture.

Knowing what PCI bus specific slots are assigned can be difficult to determine; therefore, Table 1

lists the slots for Compaq PCI bridged and dual-peer PCI servers and which bus they populate.

Use this matrix to identify which slot is assigned to the primary or secondary bus.

For any servers not listed, refer to the server user guide for the slot information or the Compaq

and Microsoft Windows NT Frontline Partnership web site located at:

http://www.compaq.com/solutions/frontline/pciutils.html.

TABLE 1: PCI BUS TO SLOT NUMBER ASSIGNMENTS

Slot

Number Bridged PCI

Bus Systems Dual-Peer PCI Bus Systems

ProLiant 2500 ProLiant 1200 ProLiant 1600 ProLiant 3000/

ProLiant 5500 ProLiant 5000 ProLiant 6000/

ProLiant 7000 ProLiant 6500

1 Secondary Secondary Secondary Primary Primary

2 Secondary Secondary Secondary Primary Secondary Primary

3 Secondary Secondary Secondary Primary Secondary Primary Secondary

4 Primary Primary Primary Primary Secondary Primary Secondary

5 Primary Primary Primary Secondary Primary Primary Secondary

6 Primary Primary Primary Secondary Primary Primary Secondary

7 Secondary Primary Secondary Secondary

8 Secondary Primary Secondary Secondary

9Secondary

10 Secondary

11 Secondary

WHITE PAPER (cont.)

ECG073/0398

PCI LOAD BALANCING

One key to procuring peak server performance is optimal configuration of the I/O (Input/Output)

subsystems. Because of architectural changes and enhancements incorporated into these systems,

careful consideration of load balancing must be given before the initial system setup and

configuration take place.

For example, the Intel Pentium Pro processor is optimized for performance using PCI peripherals.

The Compaq ProLiant servers that support dual-peer PCI bus architectures provide aggregate I/O

throughput capability as high as 267 MB/s. The dual-peer PCI bus architecture increases

configuration flexibility and allows higher levels of overall performance. However, attaining

peak performance requires careful evaluation of I/O loading across both PCI buses. This means

the administrator must carefully plan expansion slot usage for each device before initial

configuration, as well as plan for future expansion.

Performance Optimization Using PCI Bus Balancing

Bus balancing is achieved by balancing the I/O throughput on each bus, thus producing the

optimum performance on a system. However, not all PCI systems (i.e., bridged PCI systems)

achieve performance gains when implementing bus balancing; therefore, the customer has to

know when to balance the load on the system. Here are some brief recommendations. Detailed

configurations are described later in the document:

•For bridged architectures, load balancing is not required nor recommended. To obtain the

best performance on a bridged PCI system, the primary bus should be populated first.

•For dual-peer architectures load balancing is recommended. It could be helpful to split the

workload between buses when I/O throughput is high.

•For dual-peer architectures that have PCI Hot Plug slots, customers must consider the

trade-off between high availability and high performance. This is discussed in more detail

later in this document.

Bus Balancing Rules

Understanding how to balance the PCI load on a system can be confusing; therefore, some general

guidelines or rules for balancing bus traffic are provided:

1. When installing multiple network or array controllers, split the controllers between the buses.

2. If installing an "odd" number of controllers, for example, two NICs (Network Interface

Controller) and one drive array controller, split the two network controllers between the

buses. Network controllers consume more bandwidth than arraycontrollers do, so it is best to

split the workload between two buses if possible.

3. Avoid putting two network controllers together in the same bus unless both buses already

have a network controller installed. Note that it is better to have a system with one dual-port

NIC in each bus than to have two single-port NICs in each bus.

WHITE PAPER (cont.)

ECG073/0398

Example Configurations

Table 2 explains where to place controllers to enable PCI bus balancing on Compaq ProLiant

servers that contain the dual-peer bus architecture. For example, a system configuration might

consist of one NIC and two drive array controllers (configuration #3 highlighted in Table 2). As

demands change and the system bandwidth needs to increase, the system administrator changes

the configuration to add another NIC to the system. As shown in configuration #4 (highlighted in

Table 2), the system administrator should place the new network controller on Bus X so the PCI

bus remains balanced.

TABLE 2: PCI BUS BALANCING IN A DUAL-PEER ARCHITECTURE

Config

#Device Type Bus X* Bus Y*

1 1 Network Interface Controller

1 Drive Array Controller Drive Array Controller Network Interface Controller

2 2 Network Interface Controllers

1 Drive Array Controller Network Interface Controller

Drive Array Controller Network Interface Controller

31 Network Interface Controller

2 Drive Array Controllers Drive Array Controller Network Interface Controller

Drive Array Controller

42 Network Interface Controllers

2 Drive Array Controllers Network Interface Controller

Drive Array Controller Network Interface Controller

Drive Array Controller

5 2 Network Interface Controllers

3 Drive Array Controllers Network Interface Controller

2 Drive Array Controllers Network Interface Controller

Drive Array Controller

6 3 Network Interface Controllers

2 Drive Array Controllers 2 Network Interface Controllers

Drive Array Controller

Optimal Preference:

1 DualPort Network Interface Controller

1 Drive Array Controller

Network Interface Controller

Drive Array Controller

Optimal Preference:

1 Network Interface Controller

1 Drive Array Controller

7 2 Network Interface Controllers

4 Drive Array Controllers Network Interface Controller

2 Drive Array Controllers Network Interface Controller

2 Drive Array Controllers

8 2 Network Interface Controllers

5 Drive Array Controllers Network Interface Controller

3 Drive Array Controllers Network Interface Controller

2 Drive Array Controllers

9 3 Network Interface Controller

4 Drive Array Controllers 2 Network Interface Controllers

2 Drive Array Controllers

Optimal Preference:

1 DualPort Network Interface Controller

2 Drive Array Controllers

Network Interface Controller

2 Drive Array Controllers

Optimal Preference:

1 Network Interface Controller

2 Drive Array Controllers

* Bus X and Y have no bearing to the primary and secondary bus. It could be either.

WHITE PAPER (cont.)

ECG073/0398

PCI BUS LOADING WITH PCI HOT PLUG

For servers with PCI Hot Plug slots on a single bus, customers must pay close attention to

requirements for availability and determine whether a trade-off is needed between high

availability and high performance. Consider the following scenarios:

Configuration 1

For high availability and high performance, place the active controllers in the hot-plug slots, with

the standby controllers in the non-hot-plug slots. This splits the load so that a single NIC and

array controller is on each bus, as shown in Table 3.

This configuration provides moderately high availability along with high performance. However

since the standby network controller (#4) is in a non-hot-plug slot, if it were to fail replacing the

controller would require shutting down the server. The active NIC (#3), on the other hand, is still

available and in a hot-plug slot thus allowing the system administrator time to replace the failed

NIC (#4) during non-peak hours, when access to the server is at a minimum.

This configuration uses the minimum number of PCI hot-plug slots while providing redundancy

to controllers. It also enables hot replacement of the primary devices (active) in the event that

any of the active controllers should fail.

TABLE 3: HIGH AVAILABILITY AND HIGH PERFORMANCE

#Device Type PCI Hot Plug Slot Non-PCI HotPlug Slot

1 SMART 2/P Drive Array (Active) XXXXXX

2 SMART 2/P Drive Array (Standby) XXXXXX

3 NetFlex-3/P Controller (Active) XXXXXX

4 NetFlex-3/P Controller (Standby) XXXXXX

Configuration 2

If high availability is a primary concern, place all four controllers (active and standby) in the

hot-plug slots as shown in Table 4. Even though this configuration breaks rule number three in

the "Bus Balancing Rules" section, having two network controllers on the same bus does not

impact performance since the second NIC is in standby mode and therefore generates minimal

traffic on the bus.

This configuration works well for high availability because the I/O traffic emitted here is not

enough to saturate the PCI bus; therefore, there is no bottleneck to slow I/O traffic. If only two

NICs and two drive array controllers are needed, as in Table 4, both drive arrays and network

controllers could be placed on same bus without receiving any performance degradation.

TABLE 4: HIGHER AVAILABILITY AND HIGH PERFORMANCE

#Device Type PCI Hot Plug Slot Non-PCI HotPlug Slot

1 SMART 2/P Drive Array (Active) XXXXXX

2 SMART 2/P Drive Array (Standby) XXXXXX

3 NetFlex-3/P Controller (Active) XXXXXX

4 NetFlex-3/P Controller (Standby) XXXXXX

WHITE PAPER (cont.)

ECG073/0398

Configuration 3

When the configuration consists of an additional stand-alone device, for example, a network

controller pair plus a single network controller, the active NIC should be on separate bus. If, on

the other hand, the customer has an arraycontroller pair plus a single arraycontroller, the active

array controllers should be on the same bus for best performance. Placing the stand-alone array

controller in a hot-plug slot provides similar performance to placing it in the non-hot-plug slot.

Since the performance is similar, using a hot-plug slot provides additional availability.

Table 5 displays a configuration using an additional stand-alone NIC. Placing the stand-alone

NIC in a non-hot-plug slot provides the best performance, as this configuration splits the active

NICs between buses. If availability is of greater concern than performance, place the stand-alone

NIC in a hot-plug slot.

TABLE 5: HIGH AVAILABILITY FOR ADDITIONAL STAND-ALONE DEVICES

#Device Type PCI Hot Plug Slot Non-PCI HotPlug Slot

1 SMART 2/P Drive Array (Active) XXXXXX

2 SMART 2/P Drive Array (Standby) XXXXXX

3 NetFlex-3/P Controller (Active) XXXXXX

4 NetFlex-3/P Controller (Standby) XXXXXX

5 NetFlex-3/P Controller (Stand-alone) XXXXXX

Configuration 4

For multiple pairs of network controllers, the same general guidelines apply. The customer must

evaluate the importance of availability and weigh that against any potential non-optimal

performance configurations.

Configuration 4 offers better availability than Configuration 3. Performance is optimal and a

higher level of availability is achieved. In the third configuration, if the standby network

controller failed, no network users would have access to any resources on that server while the

system administrator shuts down the system to replace the failed controller.

NOTE: A controller pair is

defined as two Compaq NICs that

are configured so that network

connectivity is maintained, even if

a connection is lost or a

controller fails. For more

information, refer to the white

paper "The Compaq Advanced

Network Error Correction

Support in a Microsoft Windows

NT Server Environment."

WHITE PAPER (cont.)

ECG073/0398

If controller #5 fails in Configuration 4, network traffic would be "switched" or routed over to the

standby controller (#6), creating a slight decrease in performance because the bus is no longer

balanced. To eliminate the performance degradation, manually switch controller #3 to standby

mode and controller #4 to active mode, thus achieving a balanced load again. For details on how

to manually switch controllers using this utility, refer to the following white papers online at:

http://www.compaq.com/support/techpubs/index.html.

•Compaq Advanced Network Error Correction Support using PCI Hot Plug with Microsoft

Windows NT

•Advanced Network Fault Detection and Correction Feature for NetWare

Another benefit in using this configuration is that if a controller fails, the system administrator

can schedule downtime during non-business hours to replace the failed NIC. Once the

administrator, however, replaces the failed controller, the original controller should be switched

back to being the active controller.

The only limitation in this configuration is that one of the active network controllers is located in

a non-hot plug slot and therefore cannot be replaced while the system is running.

TABLE 6: HIGH AVAILABILITY FOR MULTIPLE NETWORK PAIRS

#Device Type PCI Hot Plug Slot Non-PCI HotPlug Slot

1 SMART 2/P Drive Array (Active) XXXXXX

2 SMART 2/P Drive Array (Standby) XXXXXX

3 NetFlex-3/P Controller (Active) XXXXXX

4 NetFlex-3/P Controller (Standby) XXXXXX

5 NetFlex-3/P Controller (Active) XXXXXX

6 NetFlex-3/P Controller (Standby) XXXXXX

PCI Hot Plug Balancing Review

Overall, the key to balancing the PCI bus is keeping the amount of data traffic on each bus

balanced. Use the following list of guidelines as a review for PCI Hot Plug bus balancing.

•When adding new controllers, keep the system balanced (see Table 2 for detailed

information).

•Evaluate the importance of high availability and weigh that against any potential non-optimal

performance configurations.

•If a controller fails, rebalancing of the system might be necessary to keep performance

optimal.

PCI BUS BALANCING TOOLS

Compaq offers a variety of helpful tools to assist in keeping the PCI busload balanced on Compaq

servers. Some tools specifically help users optimize their system containing PCI technology. A

brief description of each tool is provided.

WHITE PAPER (cont.)

ECG073/0398

System Management Performance Monitor

Compaq offers Windows NT Performance Monitor Add-On Enhancement Tools toaid in theeasy

installation and removal ofObjectsand Object Countersfor theCompaq EISA and PCI Buses,

Power Supplyand NetFlex-3 Controllers.

TheSystem Management Performance Monitor, specifically, addsseveral System Management

ObjectstotheWindowsNT Performance Monitor. Thesecountersincludeitemsconcerning the

EISA Bus, PCI Bus, and Power Supply. Thesecounters requireCompaq Support Software

Version 1.21Aor later for Microsoft WindowsNT and Compaq Insight Manager 3.30 or later.

Thesetoolsareavailableon theCompaq Resource Paq for Microsoft WindowsNT. Toobtain a

copyoftheCompaq Resource Paq, gototheCompaq Microsoft FrontlinePartnership page

located on thewebat:

//www.compaq.com/solutions/frontline

Once theSystem Management Performance Monitor utilityisinstalled, viewthecounter data

collected bythedriversthrough thePerformance Monitor Utilityincluded with Microsoft

Windows NT.

Balancing Bus Use

Compaq Insight Manager supports bus usemeasurements on each PCI bus and on theEISA bus.

Thebususemeasurement toolsprovidea good waytocheck theI/Oconfiguration toensurethat

peripheralsareproperlybalanced across thetwoPCI buses. An indication ofunbalanced bususe

impliesthat thesystem might need tobereconfigured tooptimizeperformance. Refer toCompaq

Insight Manager documentation for moreinformation about using thesetools.

PCI BUSLOADINGWITH REDUNDANT CONTROLLERS

Compaq hasoffered manyinnovativesolutionstoreducing network downtimeon Compaq server

networks. Someofthesesolutionsinclude:

•OnlineStorageController RecoveryOption

•Compaq Advanced Network Control Utility

Online Storage ControllerRecoveryOption

TheCompaq OnlineStorageController RecoveryOption providesredundancyat themass storage

controller level bymerging twoSMART-2 controllers intoa controller pair. In such a pair, one

controller isactive, and theother remainsin standby mode. Should a problem occur with the

activecontroller, thedevice driver switchestraffictothestandbycontroller without loss ofdata or

interruption ofservice. Acompletedescription ofthisfault tolerance featurecan befound in the

whitepaper called Implementing Online Storage ControllerRecovery in WindowsNT, July 1997

– Doc ID 066A/0797.

Compaq Advanced Network Control Utility

TheCompaq Advanced Network Control Utilityisa network-monitoring tool that allowsa user to

install, uninstall, configureand monitor NetFlex-3 controllers. ThisutilityalsodisplaysPCI bus

number assignments, bustypeand slot numbersassociated with each device.

NOTE: Compaq Insight

Manager also monitors PCI bus

utilization on SCO UNIX and

Novell NetWare servers.

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