AIX 5L 64 Bit Kernel

AIX5L64-bit Kernel Planning Guide

07/19/2002

Tom MathewsJames Moody

IBM Server Group

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Page 22A.3.8 Diagnostics Frameworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 21A.3.7 Graphics Frameworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 21A.3.6 STREAMS Frameworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 21A.3.5 TTY and Printer Frameworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 21A.3.4 File System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 21A.3.3 Data Link Control Frameworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 20A.3.2 Communication Frameworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 20A.3.1 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 20A.3 Common Kernel Extension Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 20A.2.4 MCA Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 20A.2.3 Input Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 20A.2.2 Communications and Connectivity (PCI bus type) . . . . . . . . . . . . . . . . . . . . . .Page 20A.2.1 Storage Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 20A.2 I/O Support for 32-bit Kernel Only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 19A.1.3 Graphics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 19A.1.2 Communications and Connectivity (PCI bus type) . . . . . . . . . . . . . . . . . . . . . .Page 19A.1.1 Storage Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 19A.1 Common I/O Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 19Appendix A: Base AIX 5L I/O and Kernel Extension Support . . . . . . . . . . . . . . . . .Page 176.3 SP Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 176.3 Third Party Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 176.1 AIX Kernel Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 176.0 Kernel Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 165.3 Common Application Development Environment . . . . . . . . . . . . . . . . . . . . . . . . . .Page 165.2 Source Compatibility between the AIX 5L 64-bit and 32-bit Kernels . . . . . . . . . . . .Page 165.1 Binary Compatibility between AIX 5L 64-bit and 32-bit Kernels . . . . . . . . . . . . . . .Page 165.0 Application Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 154.4 CD-ROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 154.3 NFS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 154.2 JFS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 144.1.4 JFS2 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 134.1.3 Current JFS2 Functional Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 134.1.2 File System Sharing between 32-Bit and 64-Bit Kernel Systems . . . . . . . . . . . .Page 134.1.1 JFS to JFS2 Data Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 124.1 JFS2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 124.0 File System Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 11 3.5 Switching Kernels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 103.4 Selecting the 64-bit Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 103.3 Using a Common System Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page 93.2 Installing the 64-bit Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 93.1 Using a Common Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 93.0 System Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 82.0 System Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 41.1 64-Bit Kernel Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 41.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contents

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Page 22A.4.2 PSSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 22A.4.1 File Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 22A.4 Kernel Extensions Support for 32-bit Kernel Only . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contents

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1.1 Introduction AIX 5L for POWER provides a new, scalable 64-bit kernel in addition to the previouslyavailable 32-bit kernel. With the addition of the 64-bit kernel, AIX is positioned forvirtually unlimited scalability on future systems, well beyond the largest system sizealready offered, the IBM eServer pSeries 690. Analogously to AIX 4.3�s introduction of64-bit application support, the AIX strategy remains that 64-bit and 32-bit arecomplementary in supporting a large range of POWER systems offerings, and that nowincludes the kernel environment.

1.1 64-Bit Kernel Overview The AIX 5L for POWER 64-bit kernel offers:

! Higher capacity hardware system support

The 64-bit kernel environment uses 64-bit addressing exclusively and enjoys avast virtual kernel address space that is capable of supporting higher capacityhardware systems with larger numbers of processors and I/O devices, as wellas larger amounts of physical memory.

! Significant system software resource scalability

Through its large kernel address space, the 64-bit kernel is also capable ofsupporting vast amounts of system software resources. These system softwareresources are required to support application work components, such asprocesses, threads, shared memory segments, and open files.

! Future growth path

The scalable kernel programming interfaces of the 64-bit kernel canaccommodate larger sizes and capacities, offering greater functionality and thecapability to accommodate future requirements. Within these programminginterfaces, parameters such as size, capacity, flags or option specifications areprovided as 64-bit quantities. In the 32-bit kernel environment, these interfacesare confined to a more restrictive 32 bits .

! Scalable kernel extensions and device drivers

Under the 64-bit kernel, all kernel extensions and device drivers are 64-bit andenjoy the scalability of the 64-bit kernel virtual address space and programminginterfaces.

! New JFS2 scalable file system for use with the 64-bit kernel

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AIX 5L for POWER 64-Bit Kernel Introduction

AIX 5L introduces the Enhanced Journal File System (JFS2). The JFS2 is anew, robust, and highly scalable journaling file system which extends thescalability of the 64-bit kernel system environment.

! Common administration, independent of kernel choice

The 64-bit kernel is simply a new installation option. Beyond this, base systemadministration is common between AIX 5L 64-bit and 32-bit kernel systems andfamiliar to AIX 4.3 customers.

! Efficient data transfer

The 64-bit kernel makes efficient use of the 64-bit PowerPC hardware,particularly when performing memory-to-memory transfers. The efficiency ofthese transfers is an important component of system performance and isoptimized by the 64-bit kernel through the full use of 64-bit hardware registersin performing these transfers.

! Equivalent 32-bit and 64-bit application support

The 64-bit kernel supports both 32-bit and 64-bit applications , as does the AIX5L 32-bit kernel on 64-bit hardware systems. The 32-bit and 64-bit applicationbinary interfaces (ABIs) are identical, whether a system is running the 64-bitkernel or the 32-bit kernel. With common ABIs between the kernels,well-behaved application binaries are portable between AIX 5L systems,independent of the bitness of the running kernel. Ill-behaved applicationbinaries are discussed in the detailed planning section later in this document.

The 32-bit ABI in AIX 5L is unchanged from that in AIX 4.3 . Compared with AIX4.3, AIX 5L provides a more scalable ABI for 64-bit applications. Thisscalability is provided through the increased size of some system -derived datatypes, such as blkcnt_t and dev_t . These large data types allow for morescalable 64-bit applications. The common scalable 64-bit ABI is supported byboth the AIX 5L 64-bit kernel and the AIX 5L 32-bit kernel. As a result, theprevious AIX 4.3 64-bit ABI is not supported under AIX 5L. To move existing64-bit applications from AIX 4.3 to AIX 5L requires recompiling the applicationsource code, and possibly changing application source code to ensure thatdata types are used correctly and consistently.

! Complementary hardware system support

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AIX 5L 64-bit kernel is complementary to the 32-bit kernel in supporting a large range of POWER hardware systems. This support consists of:

Processor Support

The 64-bit kernel supports 64-bit POWER hardware systems based onthe following processors:

! RS64 I, II, III, IV! POWER4

The AIX 5L 32-bit kernel supports all current POWER hardware systems,up to its hardware configuration limits, such as maximum 96 Gb of physicalmemory supported, or up to its resource scalability limits, such as themaximum limit of 1 million of open files supported.

Large Memory Hardware ConfigurationsWhile both the 32-bit and 64-bit kernel are supported on POWER4hardware systems, the 64-bit kernel must be used for POWER4configurations that contain more than 96 Gb of physical memory if allphysical memory is to be used. The 32-bit kernel only supports up to 96Gb of physical memory, while the 64-bit kernel supports the initialPOWER4 hardware system maximum memory configuration of 256 Gb.

The maximum memory configuration for current RS64 hardware systemsis not above 96 GB, so physical memory size alone does not drive Power64-bit customers in the direction of the 64-bit kernel.

Minimum Hardware System Requirements

The 64-bit and 32-bit kernels have the same minimum hardware systemrequirements. These requirements consist of 64 Mb of physical memory,128 Mb of initial disk paging space, and 536 Mb of disk storage to containthe base AIX operating system installation image.

The equivalence of support for both 32-bit and 64-bit applications, along with thecomplementary approach to supporting 64-bit hardware systems with both kernelenvironments in AIX 5L, provides customers with the flexibility to plan for smoothmigrations to large system environments where the 64-bit kernel becomes a necessity.The following sections describe the considerations and recommendations fordetermining how to make use of this flexibility.

1.2 64-Bit Kernel Usage GuidelinesThe general kernel usage guidelines are given below.

The 64-bit kernel is recommended to be used:

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! If the hardware system configuration is greater than 16-way multiprocessorand/or greater than 96 Gb of physical memory.

! If the desired device drivers and kernel extension are 64-bit.

The 32-bit kernel is required to be used:

! On 32-bit only hardware systems.

! If desired middleware is available through 32-bit kernel extensions only.

! In a Scalable Parallel (SP) environment. A 64 bit enabled cluser solution isplanned for the Fall of 2002 running on AIX 5.1.

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2.0 System LimitsThrough its scalable kernel address space and interfaces, the 64-bit kernel architecturecan support system limits that are virtually unlimited. This means limits for applicationwork components, like the system-wide maximum number of processes, threads, openfiles or shared memory segments, are practically unconstrained by the 64-bit kernelarchitecture. Supported limits do exist for the 64-bit kernel that are below itsarchitectural limits, but these lower limits are dictated by application interface standardsor emerging customer requirements. As standards change and customer requirementsincrease, the 64-bit kernel is more than capable of scaling up to support higher limits.

The 32-bit kernel uses a restricted 32-bit kernel address space and kernel interfacesand has limited scalability and lower supported system limits than the 64-bit kernel. Asan example, the 32-bit kernel supports a maximum of over 1 million open files. This isboth a current and architectural limit. The 64-bit kernel�s maximum is over 3 millionopen files and can easily be extended beyond this number in the future.

System limits are also relevant to hardware configurations. In particular, the 32-bitkernel is only capable of supporting 96 Gb of physical memory. On the other hand, the64-bit kernel currently supports up to 256 Gb of phy sical memory, but canarchitecturally support up to 16 Tb. This detail is important for POWER4 customersbecause these hardware systems support physical memory sizes beyond 96 Gb and upto 256 Gb. Beyond the external limits discussed above, system limits that are internal to the kernelmay also be relevant to particular customer environments because they can affectsystem scalability, performance, and throughput. The 64-bit kernel extends internallimits beyond those found under the 32-bit kernel.

Customers must fully consider system limits when determining whether the 64-bit kernelis required for their environments. In most cases, physical memory configurations arethe deciding factor. However, a customer may choose the 64-bit kernel due to aspecific limitation of the 32-bit kernel.

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AIX 5L for POWER 64-bit Kernel System Limits

3.0 System Administration Base system administration tasks are predominantly common be tween AIX 5L 64-bitand 32-bit kernel systems and are supported through a common set of utilities, tools,and interfaces that are familiar to AIX 4.3 customers. This commonality and familiarityextends to the manner in which AIX 5L systems are maintained and serviced.

Base system administration differs in only two areas:

! An administrator can select from two kernels at the time the base operatingsystem is installed. This is a straightforward task and adds little complication tothe installation process. The details of 64-bit kernel install ation and selectionare provided below within this section.

! The 64-bit and 32-bit kernel system use different file system types for the rootvolume group file systems, with the JFS2 used for 64-bit kernel and JFS usedfor 32-bit kernel. Slightly different administration is required between the JFSand JFS2. These differences are detailed below in the sec tion of thisdocument that discusses the 64-bit kernel file system environment.

3.1 Using a Common KernelThe common base system administration supported by AIX 5L makes it easy forcustomers to migrate from the 32-bit kernel to the 64-bit kernel. It also makes it simpleto administer systems in environments where a mixture of 64-bit and 32-bit kernelsystems are used. To further simplify system administration, administrators can chooseand use the one kernel that is most appropriate acr oss all their hardware systems andworkload environments. This is because use of a common kernel permits customers tomaintain and service only a single level of the AIX 5L operating system.

3.2 Installing the 64-bit KernelThe 64-bit kernel is packaged in the bos.mp64 fileset and automatically installed on64-bit POWER hardware systems with the AIX 5L base operating system. The 64-bitkernel extensions supported through the AIX 5L base operating system are provide d asdual mode kernel extensions and are also automatically installed on both 32-bit and64-bit hardware systems.Dual mode kernel extensions are supported by both the 64-bit and 32-bit kernels andare provided through a single archive file that contains both the 64-bit and 32-bitversions of a kernel extension. Based upon the bitness of the running kernel, theappropriate version of the kernel extension is automatically selected from the archivefile by the AIX 5L kernel loader at kernel extension load time. The AIX 5L kernel loaderalso supports single mode kernel extensions. A single mode kernel extension is a64-bit or 32-bit version of the kernel extension contained within a flat file.

AIX 5L for POWER 64-Bit Kernel System Administration

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3.3 Using a Common System BaseDual mode kernel extensions are used to support a common AIX 5L system base.Under this base, kernel extensions, libraries, commands and utilities, header files, andsystem-related files, such as stanza files, are common between the 64-bit and 32-bitkernels and supported through common files. Outside o f the actual binaries for the64-bit and 32-bit kernel, only a few kernel-specific files exist, consisting of the fewkernel extensions that are only provided under the 32-bit kernel to support oldertechnology, such as I/O devices that are near end-of-life.The common AIX 5L system base provides a number of benefits:

! It supports common functionality and system administration between 64-bitand 32-bit kernel systems.

! Only a single system base need be installed and supported for both the 64-bitand 32-bit kernels. This simplifies AIX base operating system installation andmaintenance, particularly in customer environments where both kernels are tobe used.

! The common system base allows customers to switch between the 32-bit and64-bit kernels without requiring a reinstallation.

3.4 Selecting the 64-bit KernelBy default, the 32-bit kernel is used when a 64-bit hardware system is initially installed.To choose the 64-bit kernel, it must be selected from the Advanced Options panel ofthe AIX installation dialogs. As shown in the following example of this panel, toggleoption 3 to yes to select the 64-bit kernel.

Example 1:Advanced Options Panel


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Advanced Options

Either type 0 and press Enter to install with current settings, or typethe option

1 Install Configuration...............Default

2 Install Trusted Computing Base......No

3 Enable 64-bit Kernel/JFS2 Support...No

>>> 0 Install with the current settings listed above.

88 Help ?99 Previous Menu

>>> Choice [0]: _

As seen in the example, selecting the 64-bit kernel from the Advanced Options panelnot only selects the 64-bit kernel, but also the new AIX 5L JFS2 file system as well.Here, selection of the JFS2 means that root volume group file systems that are createdas part of the base installation (that is, /, /usr, /var, /tmp, /home) will be JFS2 filesystems.

3.5 Switching KernelsAs previously indicated, it is possible to switch kernels without reinstalling the AIX 5Lbase operating system. This requires a system reboot and can be done through theseries of commands provided below. Note that root authority is required for thisprocedure. Also, the bold UNIX (unix) indicated in the example procedure below shouldbe the kernel binary within /usr/lib/boot for the kernel that is to be switched to. Thekernel binary for the 64-bit kernel is unix_64 while those for the MP and UP 32-bitkernel are unix_mp and unix_up, respectively.

# create a /unix symlink to the desired kernel binary$ ln -sf /usr/lib/boot/unix /unix

# also create a /usr/lib/boot/unix symlink to the desired kernel$ ln -sf /usr/lib/boot/unix /usr/lib/boot/unix

# write a new kernel image to the boot device$ bosboot -ad /dev/ipldevice

# reboot$ shutdown -r

The capability to easily switch kernels may be valuable for test environments in whichapplications and kernel extensions must be tested under both the 64-bit and 32-bitkernels.


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4.0 File System EnvironmentThe 64-bit kernel supports the JFS2, JFS, and CD-ROM physical file systems, as wellas the NFS distributed file system.

4.1 JFS2The enhanced Journaled File System (JFS2) available on AIX 5L is a next-generationversion of the JFS found on AIX 4.3 and previous releases. In addition to supportin gfast system restart and improved file system metadata consistency through journaling,JFS2 introduces several key scalability and performance features. These featuresinclude extent-based allocation, efficient directory organizations, dynamic file systemobject allocation, current support for 1 Tb file systems and files, and architecturalsupport for 4 Pb file systems and files. While tailo red primarily for the high throughputand reliability requirements of servers, JFS2 is also applicable to client configurationswhere performance and reliability are desired.

While AIX 5L enhances customer flexibility by providing support for both the new JFS2and older JFS file systems, selecting the 64-bit kernel at base AIX installation time willcreate the root volume group file systems as JFS2 file systems. Selecting the 32-bitkernel at AIX 5L installation time will cause the root volume group file systems to becreated using JFS, due to the resource constraints and restricted performance imposedon JFS2 by the 32-bit kernel environment. When creating additional file systems on systems using the 64-bit kernel, it isrecommended that JFS2 be used, unless there is an overriding reason to select JFS.JFS2 provides excellent performance, scalability and large file system and filecapacities in the 64-bit kernel environment and is the strategic physical file system forAIX. This is why JFS2 is used for the root volume group file systems.Some overriding reasons for selecting JFS file systems in the 64-bit kernel environmenton AIX 5L could be due to the need to export the disks and file system to other pre-AIX5L systems for data sharing or backup. Other less common reasons include the slightdifferences in JFS2 administration with respect to command line options when usingshell scripts to administer file systems, as well as some differences in the extendedfunctions offered by JFS, not found on JFS2. These issues will be discussed in moredetail in the following paragraphs. Customers installing the AIX 5L 32-bit kernel environment can create either JFS orJFS2 files systems. Both file system implementations are fully supported, however, theJFS2 file system may not perform as well under the 32-bit kernel as it does on the64-bit kernel. This is due to the resource-constrained environment of the 32-bit kernel.JFS2 file systems should be created if it is expected that the disks and file system dataare to be shared with other systems using the 64-bit kernel.

AIX 5L for POWER 64-bit Kernel File System Environment

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4.1.1 JFS to JFS2 Data MigrationFor customers to move their existing data from JFS file systems onto the higherperformance, more scalable JFS2 file systems, it is possible to migrate this data toJFS2 file systems using two different approaches:

! Back up the JFS file system to tape, remove it and create a JFS2 file system inits place. Then restore the tape backup to the newly created JFS2 file system.

! If there is enough disk space available, it is possible to create a new JFS2 file system and copy all files from the JFS file system to the JFS2 file system , thendelete the JFS file system.

We recognize that both approaches are time-consuming in the face of customerenvironments with large volumes of JFS data. Both approach es may also require theJFS file system to be quiesced in some customer environments so that consistentbackups or copies can be made. Therefore customers who want to move to JFS2should create all new file systems using JFS2, and migrate their existing JFS datawhen convenient.

4.1.2 File System Sharing between 32-Bit and 64-Bit Kernel SystemsCustomers who want to move disks containing data between a mixture of AIX 4.3 andAIX 5L systems and/or a mixture of systems using the AIX 5L 32-bit and 64-bit kernelenvironments should follow these recommendations:

! If the disks are to be moved between AIX 4.3 and AIX 5L systems, JFS must beused as the file system type.

! If the disks are to be predominantly used on AIX 5L systems with the 32-bitkernel, and only occasionally on AIX 5L system using the 64-bit kernel, JFSshould be used as the file system. This is due to the restricted performancecharacteristics of the JFS2 on the resource-constrained 32-bit kernel.

! Customers using HACMP High Availability environments must use JFS filesystems.

! If the disks are to be predominantly used on AIX 5L systems with the 64-bitkernel, and only occasionally on AIX 5L using the 32-bit kernel, JFS2 should beused as the file system unless there is a functional requirement (describedbelow) dictating the use of JFS. This will provide the full benefits of JFS2 onsystems using the 64-bit kernel, while providing full support of data access onthe 32-bit systems as well.

4.1.3 Current JFS2 Functional DifferencesMost key functions found on JFS are also provided on JFS2. However, some JFSfunctionality is not being carried forward to JFS2. Other functionality has been staged .Support for that functionalilty is planned on JFS2 in the near future. This JFSfunctionality that will not be supplied on JFS2 is as follows:

! No integrity mount


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This option disabled journaling with the JFS to avoid the performance cost ofmaintaining file system integrity for scratch file systems that were re-created atsystem startup.

! File compressionThis option optimized disk space utilization by compressing user file data at thelogical block level.

! Deferred update open modeThis open mode option allowed an application to defer writes to disk of modifiedfiles unless explicitly committed by the application by a file sync operation .

Current JFS functionality that will be supplied on JFS2 in a future release is as follows:! User quotas

This functionality consists of user and group level quota support for file systemdisk space usage.

! Data Management Application Programming Interfaces (DMAPI)DMAPI support is required for a physical file system to be support ed through somehierarchical storage managers, such as products from Veritas.

! Snapshot backupThis functionality provides support for the LVM snapshot backup capability forlogical volumes that contain JFS file systems.

! HA/NFS supportHA/NFS is a component of HACMP and supports the takeover of NFS requestsfrom a failed server using JFS file systems.

If a customer environment is strictly dependent on functionality listed above, JFS mustbe used in that environment.

4.1.4 JFS2 AdministrationLike JFS, JFS2 can be administered through Web-based System Management, SMIT,the command line or through the use of batch files. Options exist for creating,modifying, dynamically extending and deleting JFS2 file systems analogous to JFS.Advanced options providing improved capabilities on JFS2, however, differ slightlyfrom JFS. JFS2 supports variable block size (providing function similar to JFSfragments), inline logs and dynamic i-node allocation. JFS2 also provides a defragmentutility similar to that found on JFS. The full set of UNIX archive utilities support JFS2, aswell as JFS file systems, including the AIX-specific backup and restore commands.However, LVM-based snapshot backup is not yet supported with JFS2 file systems.Customer-created batch files used for administering JFS file systems may have to beslightly modified to support the extended options of JFS2. In this case, common batchfiles can be used, as long as file system type is checked and commands issuedaccordingly.


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4.2 JFSAs stated, customers may continue to use existing JFS file systems and create newones in an installation using the 64-bit kernel. However, the JFS has limited scalabilityand performance in comparison to the JFS2 and may be a poor choice for somecustomer environments. In particular, the JFS2 is a much better choice forenvironments where large files are in use or where large file systems are required.Although JFS2 is automatically used for the root volume group file systems that arecreated as part of initial AIX installation when the 64-bit kernel is selected, the JFS canbe used for these file systems. To do this, a customer should first select the 32-bitkernel for the initial AIX installation and then switch to the 64-bit kernel through theprocedure given in the previous section. Selecting the 32-bit kernel at initial installationcauses the root volume group file systems to be created as JFS file systems.

4.3 NFSThe NFS support provided under the 64-bit kernel is fully consistent with that providedunder the 32-bit kernel, so no special consideration is required for using NFS under the64-bit kernel.

4.4 CD-ROMLike NFS, CD-ROM file system support is consistent between the 64-bit and 32-bitkernels.


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5.0 Application SupportThe application support provided under the AIX 5L 32-bit and 64-bit kernels ispredominantly common and compatible. This allows AIX 5L customers to use commonapplication binaries and source code regardless of which kernel they use. It also easesthe migration from the 32-bit kernel to the 64-bit kernel.

5.1 Binary Compatibility between AIX 5L 64-bit and 32-bit KernelsThe vast majority of application binaries built for AIX 5L are compatible between AIX 5Lsystems, independent of the bitness of the active kernel. Compatibility between AIX 5L32-bit and 64-bit kernel systems is not provided for binaries that:

! Rely upon kernel extensions that are not provided under both AIX 5L kernels.

! Rely upon internal kernel details, unless changed to support both kernels. ! Are built for an execution mode that is not supported by the underlying hardware (i.e. 64-bit binaries are only supported on 64-bit hardware systems).

Most notable among the application binaries that rely upon internal kernel details aremem programs which access kernel data structures within system (kernel) spacethrough /dev/mem or /dev/kmem reads and writes. The issue for these programs is thatkernel data structure and system (kernel) space differs between the 32-bit and 64-bitkernels. The number and use of mem programs is limited. If these programs are to beused between the 64-bit and 32-bit kernel, they will have to be modified to understandboth kernels.

5.2 Source Compatibility between the AIX 5L 64-bit and 32-bit KernelsApplication source code compatibility is supported between the AIX 5L 64-bit and 32-bitkernels for both 32-bit and 64-bit applications.

5.3 Common Application Development Environment A common environment is supported between the 32-bit and 64-bit kernels forapplication development. This is provided through common header files, compilers,build tools, and application level debuggers.

AIX 5L for POWER 64-bit Kernel Application Support

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6.0 Kernel ExtensionsThe 64-bit kernel requires that all kernel extensions, including device drivers, also be64-bit. AIX 5L provides a comprehensive set of 64-bit kernel extensions for the 64-bitkernel, as well as 32-bit kernel extensions for the 32-bit kernel.

6.1 AIX Kernel ExtensionsIn AIX 5L, most 32-bit kernel extensions provided for the 32-bit kernel have 64-bitcounterparts for the 64-bit kernel. However, a small subset of device drivers for older, end-of life I/O devices supported on the 32-bit kernel do not have corresponding 64 -bitdrivers, and are not supported on the 64-bit kernel. In addition, the DCE/DFS and AFSfile systems provided as kernel extensions for the 32-bit kernel are not currentlyavailable for the 64-bit kernel. IBM plans to provide the newer parallel / clustered GPFSfile system technology as an alternate to DFS for the 64-bit kernel in the near future.The availability of the distributed AFS file system for the 64-bit kernel has not beendetermined. The older I/O drivers and distributed file systems that are supported onlyon the 32-bit kernel are listed in Appendix A.

Customers who want to determine if these subsystems are installed in their currentenvironments can use the lslpp -h <package name>.* command on existing systems. Before a customer decides to replace an existing 32-bit AIX kernel environment with anAIX 5L kernel installation on an existing 64-bit hardware system, the lslpp commandcan be issued on the system to determine if a device is present that is not supported bythe 64-bit kernel.

6.3 Third Party Applications In rare cases, third party, custom application software, or middleware supplier maysupply their own kernel extension to provide some privileged function in the kernelspace. While most applications and middleware have no kernel extensions, it may beuseful for customers wishing to deploy the 64-bit kernel on AIX 5L to check with theirapplication or middleware supplier concerning support of the 64-bit kernel environmenton AIX 5L. In the unusual case that a required application uses a kernel extension thatis not yet available for the 64-bit kernel on AIX 5L, the customer may choose to installthe AIX 5L 32-bit kernel, or install the 64-bit kernel and obtain the 64-bit kernelextension from the application supplier. If a custom in-house application using a kernelextension has been developed by the customer for AIX, this kernel extension will needto be ported to the 64-bit kernel environment before the application can be used onsystems employing the 64-bit kernel.

6.3 SP SupportThe 64-bit kernel is not currently supported in the SP system environment. The PSSPsoftware package associated with the parallel SP environment uses kernel extensionsthat are not yet available for the 64-bit kernel environment. Therefore, the 32-bit kernelenvironment offered by AIX 5L should be installed on SP systems.

.

AIX 5L for POWER 64-Bit Kernel Kernel Extensions

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Appendix A: Base AIX 5L I/O and Kernel Extension SupportThis section details the I/O devices (device drivers) and kernel extensions that areprovided through base AIX 5L support .

A.1 Common I/O SupportThe AIX 5L for POWER 64-bit and 32-bit kernels both support the storage,communications and connectivity-related I/O devices shown below.

A.1.1 Storage Interfaces! Ultra SCSI SE and Ultra SCSI Differential ! PCI Dual Channel Ultra SCSI Adapter ! PCI 3-Channel Ultra2 SCSI RAID Adapter ! PCI 4-Channel Ultra2 SCSI RAID Adapter ! PCI 4-Channel Ultra3 SCSI RAID Adapter ! SSA Advanced Serial RAID Plus ! Gigabit Fibre Channel ! Older Fast/Wide SCSI Adapters (6208, 6209) ! SCSI RAID Adapter (SCSI-2 Fast/Wide RAID adapter) ! SCSI Disk Drives ! SSA Disk Drives ! SCSI CD-ROM ! SCSI Tape Drives (1/4 inch, 4mm, 8mm, etc.) ! Diskette Drive ! External SCSI Disk Subsystems (Oyster, Shark, 7134, 7137, 7131-105, 7027, 7203, 7204) ! External SCSI Tape & Optical Subsystems (too numerous to list) ! External Fibre Disk & Tape Subsystems (several)

A.1.2 Communications and Connectivity (PCI bus type)! EIA RS232D/EIA RS422A ! Token-Ring PCI 4/16 Adapter ! 4-port 10/100 Mbps Ethernet ! IBM Ethernet 10/100 Mbps ! 10/100/1000 Base-T Ethernet PCI Adapter ! Gigabit Ethernet ! ATM 155 Mbps ! TURBOWAYS 622 Mbps PCI MMF ATM Adapter ! 2-port Multiprotocol PCI Adapter ! Parallel Port (POWER4 and 70** Models H70, H80, M80, S00, S80, 170, 260, 270)

A.1.3 Graphics! IBM POWER GXT130P, GXT120P, GXT300P, GXT2000P, GXT3000P, GXT4000P, GXT6000P

AIX for POWER 64-bit Kernel Appendix A

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A.2 I/O Support for 32-bit Kernel OnlyThe I/O devices given below are only supported under the AIX 5L 32-bit kernel.

A.2.1 Storage Interfaces! DTXA Adapter ! SSA Multi-Initiator RAID Enhanced Loop ! Older Fast/Wide SCSI Adapters (2408, 2409) ! External SCSI Disk Subsystems (7135)

A.2.2 Communications and Connectivity (PCI bus type)! 3Com Ethernet 10/100 Mbps ! FDDI 100 Mbps ! Digital Trunk Quad/Resource Adapter ! ESCON Control Unit (Host Attach) ! ESCON Emulation (Tape Attach) ! X.25 ! BSC ! Parallel Port (RS/6000 70** Models S70, S7A) ! HIPPI ! PCI Cryptographic Coprocessor (4958) ! External Ultra3 Subsystem (DU3/TU3) Graphics Accelerators

A.2.3 Input Devices! Dials (6094-010) ! LPFK (6094-020)! Tablets (6093-011, 6093-012, 6093-021)

A.2.4 MCA Adapters! Existing AIX Version 4.3.3 MCA Adapters

A.3 Common Kernel Extension SupportThe kernel extensions supported by both the AIX 5L 64-bit and 32-bit kernel are shownbelow.

A.3.1 Storage! LVM

A.3.2 Communication Frameworks! TCP Protocol ! Raw Network Interfaces ! BSD-Style Network Interface ! Berkeley Packet Filter ! Quality of Service ! Ethernet Demuxer ! Token Ring Demuxer


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! HDLC Demuxer ! ATM Demuxer ! Point-to-Point LCP ! Point-to-Point HDLC ! Point-to-Point IP ! IPSEC ! ATM Call Manager ! ATM LANE

A.3.3 Data Link Control Frameworks! Ethernet (Standard) DLC ! IEEE 802.3 Ethernet DLC ! FDDI DLC ! SDLC DLC ! Token Ring DLC

A.3.4 File System! CD-ROM File System ! Asynchronous I/O ! NFS Server ! NFS Client ! NFS CacheFS ! NFS RPC Compatibility ! NFS DES ! NFS AutoFS ! JFS Compression ! I/O Completion Ports

A.3.5 TTY and Printer Frameworks! LDTERM Framework ! LDTERM Language Support Framework ! PTY Framework ! Printer Framework ! Printer Ignore CTS Framework ! Low Function Terminal

A.3.6 STREAMS Frameworks! STREAMS ! Data Link Driver ! Packet Filter Module ! STREAMS Pipe Driver ! XTI over Sockets Driver ! XTI over Sockets Module

A.3.7 Graphics Frameworks! Shared Memory Transport ! Rendering Context Manager


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A.3.8 Diagnostics Frameworks! PDIAGX

A.4 Kernel Extensions Support for 32-bit Kernel OnlyThe kernel extensions given below are supported only by the 32-bit kernel.

A.4.1 File Systems! AFS! DCE/DFS

A.4.2 PSSP! All PSSP-related Extensions


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