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Memory mirroring, Memory performance considerations

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Memory mirroring As discussed in 1.7, "System memory" on page 19, memory mirroring is supported by the x440 for increased fault tolerance and high levels of availability. Key configuration rules relating to memory mirroring: Memory mirroring must be enabled in the BIOS (it is disabled by default). See 4.1.2, "Enabling memory mirroring" on page 108 for details. Enabling memory mirroring halves the amount of memory available to the operating system. Both ports in an SMP Expansion Module must have the same total amount of memory. Partial mirroring is not supported. When using memory mirroring, all of the DIMMs in an individual memory port (that is in both banks) must be the same size and clock speed (all memory must be 133 MHz DIMMs). DIMM sizes in one port can be different from DIMM sizes in the other port, but the total amount of memory in Port 1 must be equal to the total memory in Port 2. Important: While memory mirroring is disabled, DIMMs in one bank may be a different size from DIMMs in the second bank of the same port. This configuration is not supported if memory mirroring is enabled. The ability to hot-replace a failed DIMM or hot-add additional DIMMs is currently not supported. SMP Expansion Modules are individually configured for memory mirroring in the BIOS. This means that as well as full memory mirroring, you can also enable memory mirroring only in one SMP Expansion Module. IBM recommends against this. Memory mirroring does not work across SMP Expansion Modules. You cannot set up four 512 MB DIMMs in the bottom SMP Expansion Module to be mirrored by four 512 MB DIMMs in the top SMP Expansion Module. Memory mirroring only operates across ports in the same SMP Expansion Module. Memory performance considerations From a performance perspective, you should attempt to balance memory between SMP Expansion Modules. This is more important than maximizing memory bandwidth to a module. Make sure each SMP Expansion Module has the same amount of memory. Then, if possible, make sure each module has eight DIMMs installed. For performance reasons, consider the following: When installing eight DIMMs, install four in bank 1 (sockets 1, 3, 5, and 7) and four in bank 2 (sockets 9, 11, 13, and 15). Chapter 3. Planning 67

Section	Page
Front cover	1
Contents	5
Notices	9
Trademarks	10
Preface	11
The team that wrote this redbook	11
Become a published author	14
Comments welcome	14
Chapter 1. Technical description	15
1.1 The x440 product line	16
1.2 System partitioning	20
1.3 IBM XA-32 chipset	21
1.4 Processors	26
1.4.1 Intel Xeon Processor MP	27
1.4.2 Intel Xeon Processor DP	30
1.5 SMP Expansion Module	31
1.6 IBM XceL4 Server Accelerator Cache	33
1.7 System memory	33
1.8 PCI subsystem	37
1.9 Redundancy	38
1.10 Light Path Diagnostics	39
1.11 Remote Supervisor Adapter	41
1.12 Operating system support	42
1.13 IBM Director	44
Chapter 2. Positioning	49
2.1 xSeries 440 application solutions	50
2.1.1 Server consolidation	50
2.1.2 Enterprise applications	52
2.1.3 Infrastructure applications	54
2.1.4 Clustering	55
2.2 Why choose the x440	57
2.2.1 IBM XA-32 chipset	57
2.2.2 Intel Xeon MP and DP processors	58
2.2.3 XceL4 Server Accelerator Cache	60
2.2.4 High-performance memory subsystem	60
2.2.5 Active PCI-X	61
2.2.6 XpandOnDemand scalability	61
2.2.7 System Partition Manager	62
2.3 The benefits of system partitioning	63
2.4 Server consolidation	65
2.4.1 Types of server consolidation	65
2.4.2 Why consolidate servers	71
2.4.3 Benefits from server consolidation	71
Chapter 3. Planning	77
3.1 System hardware	78
3.1.1 Processors	78
3.1.2 Memory	79
3.1.3 PCI slot configuration	82
3.1.4 Broadcom Gigabit Ethernet controller	86
3.2 Cabling and connectivity	88
3.2.1 SMP Expansion Module connectivity	88
3.2.2 Remote Supervisor Adapter connectivity	91
3.2.3 Remote Expansion Enclosure	92
3.2.4 Serial connections	97
3.3 Storage considerations	97
3.3.1 xSeries storage solutions	98
3.3.2 Disk subsystem performance	102
3.3.3 Tape backup	103
3.4 Server partitioning and consolidation	104
3.5 Operating system considerations	104
3.5.1 Windows 2000 Datacenter Server	106
3.5.2 Microsoft Windows NT 4.0 Enterprise Edition	109
3.5.3 Microsoft Windows 2000 Server	110
3.5.4 Microsoft Windows .NET Server	111
3.5.5 Novell NetWare	111
3.5.6 Red Hat/SuSE Linux	111
3.5.7 VMware ESX Server	112
3.6 Application considerations	114
3.6.1 Scalability and performance considerations	114
3.6.2 SMP and server types	115
3.7 Rack installation	116
3.8 Power considerations	117
3.9 Solution Assurance Review	118
Chapter 4. Installation	121
4.1 System BIOS settings	122
4.1.1 Updating BIOS and firmware	122
4.1.2 Enabling memory mirroring	122
4.1.3 Enabling Hyper-Threading	123
4.2 Device drivers	125
4.3 Operating system installation	125
4.3.1 Microsoft Windows 2000 Server and Advanced Server	126
4.3.2 Red Hat Linux installation	133
4.3.3 NetWare installation	135
4.3.4 VMware ESX Server	142
4.4 Additional Information	142
Chapter 5. Management	143
5.1 Active PCI Manager	144
5.1.1 Using Active PCI Manager	146
5.1.2 Adding adapters to the system	150
5.1.3 Analyzing an existing configuration	158
5.2 System Partition Manager	164
5.3 Process Control	169
5.3.1 Process alias rules	170
5.3.2 Process execution rules	174
5.3.3 Group process execution rules	175
Abbreviations and acronyms	187
Related publications	189
IBM Redbooks	189
Referenced Web sites	189
How to get IBM Redbooks	192
IBM Redbooks collections	192
Index	193

Match case Limit results 1 per page

Chapter 3. Planning

Memory mirroring

As discussed in 1.7,

“

System memory

”

on page 19, memory mirroring is

supported by the x440 for increased fault tolerance and high levels of availability.

Key configuration rules relating to memory mirroring:

Memory mirroring must be enabled in the BIOS (it is disabled by default). See

4.1.2,

“

Enabling memory mirroring

”

on page 108 for details.

Enabling memory mirroring halves the amount of memory available to the

operating system.

Both ports in an SMP Expansion Module must have the same total amount of

memory. Partial mirroring is not supported.

When using memory mirroring, all of the DIMMs in an individual memory port

(that is in both banks) must be the same size and clock speed (all memory

must be 133 MHz DIMMs). DIMM sizes in one port can be different from

DIMM sizes in the other port, but the total amount of memory in Port 1 must

be equal to the total memory in Port 2.

The ability to hot-replace a failed DIMM or hot-add additional DIMMs is

currently not supported.

SMP Expansion Modules are individually configured for memory mirroring in

the BIOS. This means that as well as full memory mirroring, you can also

enable memory mirroring only in one SMP Expansion Module. IBM

recommends against this.

Memory mirroring does not work across SMP Expansion Modules. You

cannot set up four 512 MB DIMMs in the bottom SMP Expansion Module to

be mirrored by four 512 MB DIMMs in the top SMP Expansion Module.

Memory mirroring only operates across ports in the same SMP Expansion

Module.

Memory performance considerations

From a performance perspective, you should attempt to balance memory

between SMP Expansion Modules. This is more important than maximizing

memory bandwidth to a module. Make sure each SMP Expansion Module has

the same amount of memory. Then, if possible, make sure each module has

eight DIMMs installed. For performance reasons, consider the following:

When installing eight DIMMs, install four in bank 1 (sockets 1, 3, 5, and 7) and

four in bank 2 (sockets 9, 11, 13, and 15).

Important:

While memory mirroring is disabled, DIMMs in one bank may

be a different size from DIMMs in the second bank of the same port. This

configuration is not supported if memory mirroring is enabled.