IBM REDP-4285-00 User Manual
Chapter 4. Tuning the operating system
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Draft Document for Review May 4, 2007 11:35 am
4285ch04.fm
What flavor and version of Linux do I need?
After you have collected the business and application requirements, decide which version
of Linux to use. Enterprises often have contractual agreements that allow the general use
of a specific Linux distribution. In this case, financial and contractual benefits will most
likely dictate the version of Linux that can be used. However, if you have full freedom in
choosing the version of your Linux distribution, there are some points to consider:
of Linux to use. Enterprises often have contractual agreements that allow the general use
of a specific Linux distribution. In this case, financial and contractual benefits will most
likely dictate the version of Linux that can be used. However, if you have full freedom in
choosing the version of your Linux distribution, there are some points to consider:
– A supported Enterprise Linux or a custom made distribution?
In certain scientific environments it is acceptable to run an unsupported version of
Linux, such as Fedora. For enterprise workloads, we strongly recommend a fully
supported distribution such as Red Hat Enterprise Linux or Novell SUSE Enterprise
Linux.
Linux, such as Fedora. For enterprise workloads, we strongly recommend a fully
supported distribution such as Red Hat Enterprise Linux or Novell SUSE Enterprise
Linux.
– What version of an enterprise distribution?
Most Enterprise Linux distributions come in various flavors that differ in their kernel
version, the supported packages or features and most importantly in their level of
hardware support. Before any installation, review the supported hardware configuration
carefully as not to loose some of your hardware’s capabilities.
version, the supported packages or features and most importantly in their level of
hardware support. Before any installation, review the supported hardware configuration
carefully as not to loose some of your hardware’s capabilities.
Select the correct kernel
Enterprise Linux distributions offer several kernel packages, as listed in Table 4-1. For
performance reasons, be sure to select the most appropriate kernel for your system.
However in most cases the correct kernel will be selected by the installation routine. Keep
in mind that the exact kernel package name differs by distributions.
performance reasons, be sure to select the most appropriate kernel for your system.
However in most cases the correct kernel will be selected by the installation routine. Keep
in mind that the exact kernel package name differs by distributions.
Table 4-1 Available kernel types
What partition layout to choose?
In the Linux community, the partitioning of a disk subsystem engenders vast discussion.
The partitioning layout of a disk subsystem is often dictated by application needs, systems
management considerations, and personal liking, and not performance. The partition
layout will therefore be given in most cases. The only suggestion we want to give here is to
use a swap partition if possible. Swap partitions, as opposed to swap files, have a
performance benefit because there is no overhead of a file system. Swap partitions are
simple and can be expanded with additional swap partitions or even swap files if needed.
The partitioning layout of a disk subsystem is often dictated by application needs, systems
management considerations, and personal liking, and not performance. The partition
layout will therefore be given in most cases. The only suggestion we want to give here is to
use a swap partition if possible. Swap partitions, as opposed to swap files, have a
performance benefit because there is no overhead of a file system. Swap partitions are
simple and can be expanded with additional swap partitions or even swap files if needed.
What file system to use?
Different file systems offer different characteristics in data integrity and performance.
Additionally certain file systems might not be supported by the respective Linux
distribution or the application that is to be used. For most server installations the default
file system proposed by the installation routine will offer adequate performance. If you
have however specific requirements for minimal latency or maximal throughput we
Additionally certain file systems might not be supported by the respective Linux
distribution or the application that is to be used. For most server installations the default
file system proposed by the installation routine will offer adequate performance. If you
have however specific requirements for minimal latency or maximal throughput we
Kernel type
Description
Standard
Single processor machines.
SMP
Kernel has support for SMP and Hyper-Threaded machines. Some packages also
include support for NUMA. There may be some variant, depending on the amount
of memory, the number of CPU, and so on.
include support for NUMA. There may be some variant, depending on the amount
of memory, the number of CPU, and so on.
Xen
Includes a version of the Linux kernel which runs in a Xen virtual machine.
Note: Most recent kernels have the capability called SMP alternative which optimizes itself
at boot time. Refer to the distribution release notes for details.
at boot time. Refer to the distribution release notes for details.