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protective MBR, Data partitions

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of the disks. GPT replaces the older Master Boot Record (MBR) partitioning scheme that has been common to PCs. There are several reasons for introducing a new partitioning scheme: MBR disks support only four partition table entries and a volume size of 2 TB (terabytes). If more partitions are required then one of these partitions must be an extended partition. Only one extended partition is allowed per disk drive. Extended partitions are then subdivided into one or more logical disks. In theory, GPT disks support an unlimited number of partitions. The number of partitions' is limited only by the amount of space reserved for making partitions entries. GPT disks can grow to a very large size. This can be up to 264 logical blocks in length (logical blocks are typically 512 bytes). This equates to 18 EB (Exabytes). In practice, the maximum is less, as there are practical limitations with other parts of the system accessing this amount of disk space efficiently. GPT disks use primary and backup partition tables for redundancy and CRC32 fields for improved partition data structure integrity. For backward compatibility with legacy MBR disk tools, all GPT disks contain a protective MBR. The protective MBR, beginning in sector 0, precedes the GUID Partition Table on the disk and contains only one partition entry that appears to span the entire disk. The legacy tools are not aware of GPT and do not know how to properly access a GPT disk. The benefit of a protective MBR is that these tools will view a GPT disk as having a single encompassing (possibly unrecognized) partition, rather than mistaking the disk for one that is unpartitioned. That is why a GPT-partitioned disk appears to have an MBR. GPT disks can be converted to MBR disks and vice versa only if all existing partitioning is first deleted, with associated loss of data. To a legacy tool, the structure of any GPT disk appears to look like Figure 1-17. The protective MBR is followed by a theoretically unlimited number of data (or possibly unrecognized) partitions. Protective MBR Data partition(s) Figure 1-17 General GPT disk structure 32 IBM xSeries 455 Planning and Installation Guide Eserver

Section	Page
Front cover	1
Contents	5
Notices	9
Trademarks	10
Preface	11
The team that wrote this redbook	11
Become a published author	13
Comments welcome	14
Chapter 1. Technical description	15
1.1 Features	16
1.1.1 Comparing the x455 with the x450	16
1.1.2 Features not supported	17
1.2 The x455 base models	18
1.2.1 Front and rear views	18
1.3 System assembly	20
1.4 IBM XA-64 chipset	21
1.4.1 The processor-board assembly	23
1.4.2 The memory-board assembly	27
1.4.3 PCI-X board assembly	31
1.5 Remote Supervisor Adapter	33
1.6 RXE-100 Expansion Enclosure	35
1.7 Multinode scalable partitions	36
1.7.1 RXE-100 connectivity	38
1.7.2 Multinode configuration	39
1.7.3 Integrated I/O function support	40
1.7.4 Error recovery	40
1.8 Redundancy	41
1.9 Light path diagnostics	41
1.10 Extensible Firmware Interface	43
1.10.1 GUID Partition Table disk	45
1.10.2 EFI System Partition	47
1.10.3 EFI and the reduced-legacy concept	48
1.11 Operating system support	49
1.12 Enterprise X-Architecture	49
1.12.1 NUMA architecture	50
Chapter 2. Positioning	53
2.1 Migrating to a 64-bit platform	54
2.2 Scalable system partitioning	55
2.2.1 RXE-100 Expansion Enclosure	56
2.3 Operating system support	56
2.4 Server consolidation	57
2.5 ServerProven®	58
2.6 IBM Datacenter Solution Program	59
2.7 Application solutions	60
2.7.1 Database applications	60
2.7.2 Business logic	62
2.7.3 e-Business and security transactions	64
2.7.4 In-house developed compute-intensive applications	65
2.7.5 Science and technology industries	65
2.8 Why choose x455	66
Chapter 3. Planning	69
3.1 System hardware	70
3.1.1 Processors	70
3.1.2 Memory	71
3.1.3 PCI-X slot configuration	75
3.1.4 Broadcom Gigabit Ethernet controller	78
3.2 Cabling and connectivity	79
3.2.1 SMP Expansion connectivity	81
3.2.2 Remote Expansion Enclosure connectivity	84
3.2.3 Remote Supervisor Adapter connectivity	90
3.2.4 Serial connectivity	92
3.3 Storage considerations	93
3.3.1 xSeries storage solutions	93
3.3.2 Tape backup	98
3.4 Rack installation	99
3.5 Power considerations	101
3.6 Operating system support	101
3.6.1 Clustering	102
3.7 IBM Director support	103
3.8 Solution Assurance Review	104
3.8.1 Trigger Tool	104
3.8.2 Electronic Solution Assurance Review (eSAR)	104
Chapter 4. Installation	105
4.1 Using The Extensible Firmware Interface	106
4.1.1 EFI Firmware Boot Manager	107
4.1.2 The EFI shell	109
4.1.3 Driver Setup	117
4.1.4 Flash update	126
4.1.5 Configuration/Setup utility	132
4.1.6 Diagnostic utility	135
4.1.7 Boot Option Maintenance	136
4.2 Configuring scalable partitions	145
4.2.1 Creating a scalable partition	145
4.2.2 Booting a scalable partition	148
4.2.3 Multiple Monitors	149
4.2.4 Deleting a scalable partition	150
4.3 Installing Windows Server 2003	150
4.3.1 Important information	150
4.3.2 Preparing to install	152
4.3.3 Installation	153
4.3.4 Post-setup phase	158
4.4 Installing Linux	165
4.4.1 Linux IA-64 kernel overview	166
4.4.2 Choosing a Linux distribution	167
4.4.3 Installing SUSE LINUX Enterprise Server 8.0	170
4.4.4 Installing Red Hat Enterprise Linux AS	174
4.4.5 Linux boot process	176
4.4.6 Information about the installed system	177
4.4.7 Using the serial port for the Linux console	185
4.4.8 RXE-100 Expansion Enclosure	186
4.4.9 Upgrading drivers	187
Chapter 5. Management	189
5.1 IBM Director	190
5.1.1 Scalable Systems Manager	191
5.2 The Remote Supervisor Adapter	191
5.2.1 Connecting via a Web browser	193
5.2.2 Connecting via the ASM interconnect	198
5.2.3 Installing the device driver	199
5.2.4 Configuring the remote control password	200
5.3 Management using the Remote Supervisor Adapter	201
5.3.1 Configuring which alerts to monitor	202
5.3.2 Configuring SNMP	204
5.3.3 Sending alerts directly to IBM Director	205
5.3.4 Creating a test event action plan in IBM Director	207
5.4 Windows System Resource Manager	210
5.4.1 WSRM description	211
5.4.2 WSRM features	212
5.4.3 WSRM in the x455	213
Abbreviations and acronyms	215
Related publications	217
IBM Redbooks	217
Other publications	217
Online resources	218
How to get IBM Redbooks	222
Help from IBM	222
Index	223

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IBM

Eserver

xSeries 455 Planning and Installation Guide

of the disks. GPT replaces the older Master Boot Record (MBR) partitioning

scheme that has been common to PCs.

There are several reasons for introducing a new partitioning scheme:

MBR disks support only four partition table entries and a volume size of 2 TB

(terabytes). If more partitions are required then one of these partitions must

be an extended partition. Only one extended partition is allowed per disk

drive. Extended partitions are then subdivided into one or more logical disks.

In theory, GPT disks support an unlimited number of partitions. The number

of partitions’ is limited only by the amount of space reserved for making

partitions entries. GPT disks can grow to a very large size. This can be up to

logical blocks in length (logical blocks are typically 512 bytes). This

equates to 18 EB (Exabytes). In practice, the maximum is less, as there are

practical limitations with other parts of the system accessing this amount of

disk space efficiently.

GPT disks use primary and backup partition tables for redundancy and

CRC32 fields for improved partition data structure integrity.

For backward compatibility with legacy MBR disk tools, all GPT disks contain a

protective MBR

. The protective MBR, beginning in sector 0, precedes the GUID

Partition Table on the disk and contains only one partition entry that appears to

span the entire disk. The legacy tools are not aware of GPT and do not know how

to properly access a GPT disk. The benefit of a protective MBR is that these

tools will view a GPT disk as having a single encompassing (possibly

unrecognized) partition, rather than mistaking the disk for one that is

unpartitioned. That is why a GPT-partitioned disk appears to have an MBR.

GPT disks can be converted to MBR disks and vice versa only if all existing

partitioning is first deleted, with associated loss of data. To a legacy tool, the

structure of any GPT disk appears to look like Figure 1-17. The protective MBR is

followed by a theoretically unlimited number of data (or possibly unrecognized)

partitions.

Figure 1-17

General GPT disk structure

Data partition(s)

Protective MBR