CentOS / Red Hat Configure an NTP Client And Server

How do I configure an NTP (Network Time Protocol) client or server under CentOS / RHEL / Fedora Linux to manage the system clock over a network?

The Network Time Protocol (NTP) is used to synchronize a computer's time with another reference time source. Under CentOS / RHEL you can use NTP or OpenNTPD server software. Both package provides client and server software programs for time synchronization.

The ntp package contains utilities and daemons that will synchronize your computer's time to Coordinated Universal Time (UTC) via the NTP protocol and NTP servers. The ntp packageincludes ntpdate (a program for retrieving the date and time from remote machines via a network) and ntpd (a daemon which continuously adjusts system time). Install the ntp package:Install ntp

# yum install ntp

Simply open /etc/ntp.conf file, enter:How do I configure an NTP Client?

# vi /etc/ntp.conf
Make sure the following line exists:
server ntp.server.com
Where,

• ntp.server.com : the hostname or IP address of the site NTP server. If your ntp server located at 192.168.1.5, enter server 192.168.1.5. You can also use public ntp server located at ntp.org.

You can also run ntpd using cron:
# echo '30 * * * * root /usr/sbin/ntpd -q -u ntp:ntp' > /etc/cron.d/ntpd
The above instructs crond to run ntpd and after setting the clock just exit, and the -u option instructs it to run as the ntp user.

Configure an NTP Server

If you have lots of server and desktop system, configure your own NTP server. Your NTP server contacts a central NTP server,provided by your ISP or a public time
server located at ntp.org, to obtain accurate time data. The server then allows other machines on your network to request the time data. Our sample setup:

192.168.1.5            ==> CentOS / Fedora / RHEL NTPD Server.
202.54.1.5              ==> ISP remote NTP server.
192.168.1.0/24        ==> NTP clients including desktop systems.

First, install and enable ntpd on 192.168.1.5:
# yum install ntp
# chkconfig ntpd on
Now open /etc/ntp.conf:
# vi /etc/ntp.conf
Make sure the following line exits:
restrict default ignore
Above will deny all access to any machine, server or client. However, you need to specifically authorized policy settings. Set it as follows:

restrict 202.54.1.5 mask 255.255.255.245 nomodify notrap noquery
server 202.54.1.5

Replace 202.54.1.5 and mask with actual remote ISP or ntp.org NTP server IP. Save and close the file.

Configure NTP clients to access your NTP Server

Now, you need to allow legitimate NTP clients to access the Server. For example, allow 192.168.1.0/24 network to synchronize to this server located at 192.168.1.5. Open /etc/ntp.conf and add policy as follows:

# Hosts on local network are less restricted.
restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap

Update your firewall settings, open /etc/sysconfig/iptables.
# vi /etc/sysconfig/iptables
Add the following line, before the final LOG and DROP lines for the RH-Firewall-1-INPUT chain:

-A RH-Firewall-1-INPUT -s 192.168.1.0/24 -m state --state NEW -p udp --dport 123 -j ACCEPT

Save and close the file. Finally, start ntpd:
# service ntpd start
# service iptables restart
# netstat -tulpn

Linux Performance Monitoring and Tuning Introduction

This is the 1st article in our new series on Linux performance monitoring and tuning.
Linux system administrators should be proficient in Linux performance monitoring and tuning. This article gives a high level overview on how we should approach performance monitoring and tuning in Linux, and the various subsystems (and performance metrics) that needs to be monitored.

To identify system bottlenecks and come up with solutions to fix it, you should understand how various components of Linux works. For example, how the kernel gives preference to one Linux process over others using nice values, how I/O interrupts are handled, how the memory management works, how the Linux file system works, how the network layer is implemented in Linux, etc.,
Please note that understanding how various components (or subsystems) works is not the same as knowing what command to execute to get certain output. For example, you might know that “uptime” or “top” command gives the “load average”. But, if you don’t know what it means, and how the CPU (or process) subsystem works, you might not be able to understand it properly. Understanding the subsystems is an on-going task, which you’ll be constantly learning all the time.
On a very high level, following are the four subsystems that needs to be monitored.

• CPU
• Memory
• I/O
• Network

1. CPU

You should understand the four critical performance metrics for CPU — context switch, run queue, cpu utilization, and load average.

Context Switch

• When CPU switches from one process (or thread) to another, it is called as context switch.
• When a process switch happens, kernel stores the current state of the CPU (of a process or thread) in the memory.
• Kernel also retrieves the previously stored state (of a process or thread) from the memory and puts it in the CPU.
• Context switching is very essential for multitasking of the CPU.
• However, a higher level of context switching can cause performance issues.

Run Queue

• Run queue indicates the total number of active processes in the current queue for CPU.
• When CPU is ready to execute a process, it picks it up from the run queue based on the priority of the process.
• Please note that processes that are in sleep state, or i/o wait state are not in the run queue.
• So, a higher number of processes in the run queue can cause performance issues.

Cpu Utilization

• This indicates how much of the CPU is currently getting used.
• This is fairly straight forward, and you can view the CPU utilization from the top command.
• 100% CPU utilization means the system is fully loaded.
• So, a higher %age of CPU utilization will cause performance issues.

Load Average

• This indicates the average CPU load over a specific time period.
• On Linux, load average is displayed for the last 1 minute, 5 minutes, and 15 minutes. This is helpful to see whether the overall load on the system is going up or down.
• For example, a load average of “0.75 1.70 2.10″ indicates that the load on the system is coming down. 0.75 is the load average in the last 1 minute. 1.70 is the load average in the last 5 minutes. 2.10 is the load average in the last 15 minutes.
• Please note that this load average is calculated by combining both the total number of process in the queue, and the total number of processes in the uninterruptable task status.

2. Network

• A good understanding of TCP/IP concepts is helpful while analyzing any network issues. We’ll discuss more about this in future articles.
• For network interfaces, you should monitor total number of packets (and bytes) received/sent through the interface, number of packets dropped, etc.,

3. I/O

• I/O wait is the amount of time CPU is waiting for I/O. If you see consistent high i/o wait on you system, it indicates a problem in the disk subsystem.
• You should also monitor reads/second, and writes/second. This is measured in blocks. i.e number of blocks read/write per second. These are also referred as bi and bo (block in and block out).
• tps indicates total transactions per seconds, which is sum of rtps (read transactions per second) and wtps (write transactions per seconds).

4. Memory

• As you know, RAM is your physical memory. If you have 4GB RAM installed on your system, you have 4GB of physical memory.
• Virtual memory = Swap space available on the disk + Physical memory. The virtual memory contains both user space and kernel space.
• Using either 32-bit or 64-bit system makes a big difference in determining how much memory a process can utilize.
• On a 32-bit system a process can only access a maximum of 4GB virtual memory. On a 64-bit system there is no such limitation.
• The unused RAM will be used as file system cache by the kernel.
• The Linux system will swap when it needs more memory. i.e when it needs more memory than the physical memory. When it swaps, it writes the least used memory pages from the physical memory to the swap space on the disk.
• Lot of swapping can cause performance issues, as the disk is much slower than the physical memory, and it takes time to swap the memory pages from RAM to disk.

All of the above 4 subsystems are interrelated. Just because you see a high reads/second, or writes/second, or I/O wait doesn’t mean the issue is there with the I/O sub-system. It also depends on what the application is doing. In most cases, the performance issue might be caused by the application that is running on the Linux system.
Remember the 80/20 rule — 80% of the performance improvement comes from tuning the application, and the rest 20% comes from tuning the infrastructure components.
There are various tools available to monitor Linux system performance. For example: top, free, ps, iostat, vmstat, mpstat, sar, tcpump, netstat, iozone, etc., We’ll be discussing more about these tools and how to use them in the upcoming articles in this series.
Following is the 4 step approach to identify and solve a performance issue.

• Step 1 – Understand (and reproduce) the problem: Half of the problem is solved when you clearly understand what the problem is. Before trying to solve the performance issue, first work on clearly defining the problem. The more time you spend on understanding and defining the problem will give you enough details to look for the answers in the right place. If possible, try to reproduce the problem, or at least simulate a situation that you think closely resembles the problem. This will later help you to validate the solution you come up to fix the performance issue.
• Step 2 – Monitor and collect data: After defining the problem clearly, monitor the system and try to collect as much data as possible on various subsystems. Based on this data, come up list of potential issues.
• Step 3 – Eliminate and narrow down issues: After having a list of potential issues, dive into each one of them and eliminate any non issues. Narrow it down further to see whether it is an application issue, or an infrastructure issue. Drill down further and narrow it down to a specific component. For example, if it is an infrastructure issue, narrow it down and identify the subsystem that is causing the issue. If it is an I/O subsystem issue, narrow it down to a specific partition, or raid group, or LUN, or disk. Basically, keep drilling down until you put your finger on the root cause of the issue.
• Step 4 – One change at a time: Once you’ve narrowed down to a small list of potential issues, don’t try to make multiple changes at one time. If you make multiple changes, you wouldn’t know which one fixed the original issue. Multiple changes at one time might also cause new issues, which you’ll be chasing after instead of fixing the original issue. So, make one change at a time, and see if it fixes the original problem.

In the upcoming articles of the performance series, we’ll discuss more about how to monitor and address performance issues on CPU, Memory, I/O and Network subsystem using various Linux performance monitoring tools.

Brief overview of Unix / Linux commands

Below is a listing of each of the Unix / Linux commands currently listed on Computer Hope and a brief explanation of what each of the commands do. This is a full listing which means not all the below commands will work with your distribution and may also not work because of your privileges. Clicking on any of the commands will display additional help and information about that command.

Command	Description
a2p	Creates a Perl script from an awk script.
ac	Prints statistics about users' connect time.
alias	Create a name for another command or long command string.
ar	Maintain portable archive or library.
arch	Display the architecture of the current host.
arp	Manipulate the system ARP cache.
as	An assembler.
at	Command scheduler.
awk	Awk script processing program.
basename	Deletes any specified prefix from a string.
bash	Command Bourne interpreter
bc	Calculator.
bdiff	Compare large files.
bfs	Editor for large files.
bg	Continues a program running in the background.
biff	Enable / disable incoming mail notifications.
break	Break out of while, for, foreach, or until loop.
bs	Battleship game.
bye	Alias often used for the exit command.
cal	Calendar
calendar	Display appointments and reminders.
cancel	Cancels a print job.
cat	View or modify a file.
cc	C compiler.
cd	Change directory.
chdir	Change directory.
checkeq	Language processors to assist in describing equations.
checknr	Check nroff and troff files for any errors.
chfn	Modify your own information or if super user or root modify another users information.
chgrp	Change a groups access to a file or directory.
chkey	Change the secure RPC key pair.
chmod	Change the permission of a file.
chown	Change the ownership of a file.
chsh	Change login shell.
cksum	Display and calculate a CRC for files.
clear	Clears screen.
cls	Alias often used to clear a screen.
cmp	Compare files.
col	Reverse line-feeds filter.
comm	Compare files and select or reject lines that are common.
compress	Compress files on a computer.
continue	Break out of while, for, foreach, or until loop.
copy	Copy files.
cp	Copy files.
cpio	Creates archived CPIO files.
crontab	Create and list files that you wish to run on a regular schedule.
csh	Execute the C shell command interpreter
csplit	Split files based on context.
ctags	Create a tag file for use with ex and vi.
cu	Calls or connects to another Unix system, terminal or non-Unix system.
curl	Transfer a URL.
cut	Cut out selected fields of each line of a file.
date	Tells you the date and time in Unix.
dc	An arbitrary precision arithmetic package.
df	Display the available disk space for each mount.
deroff	Removes nroff/troff, tbl, and eqn constructs.
dhclient	Dynamic Host Configuration Protocol Client.
diff	Displays two files and prints the lines that are different.
dig	DNS lookup utility.
dircmp	Lists the different files when comparing directories.
dirname	Deliver portions of path names.
dmesg	Print or control the kernel ring buffer.
dos2unix	Converts text files between DOS and Unix formats.
dpost	Translates files created by troff into PostScript.
du	Tells you how much space a file occupies.
echo	Displays text after echo to the terminal.
ed	Line oriented file editor.
edit	Text editor.
egrep	Search a file for a pattern using full regular expressions.
elm	Program command used to send and receive e-mail.
emacs	Text editor.
enable	Enables / Disables LP printers.
env	Displays environment variables.
eqn	Language processors to assist in describing equations.
ex	Line-editor mode of the vi text editor.
exit	Exit from a program, shell or log you out of a Unix network.
expand	Expand copies of file s.
expr	Evaluate arguments as an expression.
fc	The FC utility lists or edits and re-executes, commands previously entered to an interactive sh.
fg	Continues a stopped job by running it in the foreground
fgrep	Search a file for a fixed-character string.
file	Tells you if the object you are looking at is a file or if it is a directory.
find	Finds one or more files assuming that you know their approximate filenames.
findsmb	List info about machines that respond to SMB name queries on a subnet.
finger	Lists information about the user.
fmt	Simple text formatters.
fold	Filter for folding lines.
for	Shell built-in functions to repeatedly execute action(s) for a selected number of times.
foreach	Shell built-in functions to repeatedly execute action(s) for a selected number of times.
fromdos	Converts text files between DOS and Unix formats.
fsck	Check and repair a Linux file system.
ftp	Enables ftp access to another terminal.
getfacl	Display discretionary file information.
gprof	The gprof utility produces an execution profile of a program.
grep	Finds text within a file.
groupadd	Creates a new group account.
groupdel	Enables a super user or root to remove a group.
groupmod	Enables a super user or root to modify a group.
gunzip	Expand compressed files.
gview	A programmers text editor.
gvim	A programmers text editor.
gzip	Compress files.
halt	Stop the computer.
hash	Remove internal hash table.
hashstat	Display the hash stats.
head	Displays the first ten lines of a file, unless otherwise stated.
help	If computer has online help documentation installed this command will display it.
history	Display the history of commands typed.
host	DNS lookup utility.
hostid	Prints the numeric identifier for the current host.
hostname	Set or print name of current host system.
id	Shows you the numeric user and group ID on BSD.
ifconfig	Sets up network interfaces.
ifdown	take a network interface down
ifup	bring a network interface up
isalist	Display the native instruction sets executable on this platform.
jobs	List the jobs currently running in the background.
join	Joins command forms together.
keylogin	Decrypt the user's secret key.
kill	Cancels a job.
ksh	Korn shell command interpreter.
ld	Link-editor for object files.
ldd	List dynamic dependencies of executable files or shared objects.
less	Opposite of the more command.
lex	Generate programs for lexical tasks.
link	Calls the link function to create a link to a file.
ln	Creates a link to a file.
lo	Allows you to exit from a program, shell or log you out of a Unix network.
locate	List files in databases that match a pattern.
login	Signs into a new system.
logname	Returns users login name.
logout	Logs out of a system.
lp	Prints a file on System V systems.
lpadmin	Configure the LP print service.
lpc	Line printer control program.
lpq	Lists the status of all the available printers.
lpr	Submits print requests.
lprm	Removes print requests from the print queue.
lpstat	Lists status of the LP print services.
ls	Lists the contents of a directory.
mach	Display the processor of the current host.
mail	One of the ways that allows you to read/send E-Mail.
mailcompat	Provide SunOS 4.x compatibility for the Solaris mailbox format.
mailx	Mail interactive message processing system.
make	Executes a list of shell commands associated with each target.
man	Display a manual of a command.
mesg	Control if non-root users can send text messages to you.
mii-tool	View, manipulate media-independent interface status.
mkdir	Create a directory.
mkfs	Build a Linux file system, usually a hard disk partition.
more	Displays text one screen at a time.
mount	Disconnects a file systems and remote resources.
mt	Magnetic tape control.
mv	Renames a file or moves it from one directory to another directory.
nc	TCP/IP swiss army knife.
neqn	Language processors to assist in describing equations.
netstat	Shows network status.
newalias	Install new elm aliases for user or system.
newform	Change the format of a text file.
newgrp	Log into a new group.
nice	Invokes a command with an altered scheduling priority.
niscat	Display NIS+ tables and objects.
nischmod	Change access rights on a NIS+ object.
nischown	Change the owner of a NIS+ object.
nischttl	Change the time to live value of a NIS+ object.
nisdefaults	Display NIS+ default values.
nisgrep	Utilities for searching NIS+ tables.
nismatch	Utilities for searching NIS+ tables.
nispasswd	Change NIS+ password information.
nistbladm	NIS+ table administration command.
nmap	Network exploration tool and security / port scanner.
nohup	Runs a command even if the session is disconnected or the user logs out.
nroff	Formats documents for display or line-printer.
nslookup	Queries a name server for a host or domain lookup.
on	Execute a command on a remote system, but with the local environment.
onintr	Shell built-in functions to respond to (hardware) signals.
optisa	Determine which variant instruction set is optimal to use.
pack	Shrinks file into a compressed file.
pagesize	Display the size of a page of memory in bytes, as returned by getpagesize.
passwd	Allows you to change your password.
paste	Merge corresponding or subsequent lines of files.
pax	Read / write and writes lists of the members of archive files and copy directory hierarchies.
pcat	Compresses file.
perl	Perl is a programming language optimized for scanning arbitrary text files, extracting information from those text files.
pg	Files perusal filters for CRTs.
pgrep	Examine the active processes on the system and reports the process IDs of the processes
pico	Simple and very easy to use text editor in the style of the Pine Composer.
pine	Command line program for Internet News and Email.
ping	Sends ICMP ECHO_REQUEST packets to network hosts.
pkill	Examine the active processes on the system and reports the process IDs of the processes
poweroff	Stop the computer.
pr	Formats a file to make it look better when printed.
priocntl	Display's or set scheduling parameters of specified process(es)
printf	Write formatted output.
ps	Reports the process status.
pvs	Display the internal version information of dynamic objects within an ELF file.
pwd	Print the current working directory.
quit	Allows you to exit from a program, shell or log you out of a Unix network.
rcp	Copies files from one computer to another computer.
reboot	Stop the computer.
red	Line oriented file editor.
rehash	Recomputes the internal hash table of the contents of directories listed in the path.
remsh	Runs a command on another computer.
repeat	Shell built-in functions to repeatedly execute action(s) for a selected number of times.
rgview	A programmers text editor.
rgvim	A programmers text editor.
rlogin	Establish a remote connection from your terminal to a remote machine.
rm	Deletes a file without confirmation (by default).
rmail	One of the ways that allows you to read/send E-Mail.
rmdir	Deletes a directory.
rn	Reads newsgroups.
route	Show / manipulate the IP routing table.
rpcinfo	Report RPC information.
rsh	Runs a command on another computer.
rsync	Faster, flexible replacement for rcp.
rview	A programmers text editor.
rvim	A programmers text editor.
s2p	Convert a sed script into a Perl script.
sag	Graphically displays the system activity data stored in a binary data file by a previous sar run.
sar	Displays the activity for the CPU.
script	Records everything printed on your screen.
sdiff	Compares two files, side-by-side.
sed	Allows you to use pre-recorded commands to make changes to text.
sendmail	Sends mail over the Internet.
set	Set the value of an environment variable.
setenv	Set the value of an environment variable.
setfacl	Modify the Access Control List (ACL) for a file or files.
settime	Change file access and modification time.
sftp	Secure file transfer program.
sh	Runs or processes jobs through the Bourne shell.
shred	Delete a file securely, first overwriting it to hide its contents.
shutdown	Turn off the computer immediately or at a specified time.
sleep	Waits a x amount of seconds.
slogin	OpenSSH SSH client (remote login program).
smbclient	An ftp-like client to access SMB/CIFS resources on servers.
sort	Sorts the lines in a text file.
spell	Looks through a text file and reports any words that it finds in the text file that are not in the dictionary.
split	Split a file into pieces.
stat	Display file or filesystem status.
stop	Control process execution.
strip	Discard symbols from object files.
stty	Sets options for your terminal.
su	Become super user or another user.
sysinfo	Get and set system information strings.
sysklogd	Linux system logging utilities.
tabs	Set tabs on a terminal.
tail	Delivers the last part of the file.
talk	Talk with other logged in users.
tac	Concatenate and print files in reverse.
tar	Create tape archives and add or extract files.
tbl	Preprocessor for formatting tables for nroff or troff.
tcopy	Copy a magnetic tape.
tcpdump	Dump traffic on a network.
tee	Read from an input and write to a standard output or file.
telnet	Uses the telnet protocol to connect to another remote computer.
time	Used to time a simple command.
timex	The timex command times a command; reports process data and system activity.
todos	Converts text files between DOS and Unix formats.
top	Display Linux tasks.
touch	Change file access and modification time.
tput	Initialize a terminal or query terminfo database.
tr	Translate characters.
traceroute	Print the route packets take to network host.
troff	Typeset or format documents.
ul	Reads the named filenames or terminal and does underlining.
umask	Get or set the file mode creation mask.
unalias	Remove an alias.
unhash	Remove internal hash table.
uname	Print name of current system.
uncompress	Uncompressed compressed files.
uniq	Report or filter out repeated lines in a file.
unmount	Crates a file systems and remote resources.
unpack	Expands a compressed file.
untar	Create tape archives and add or extract files.
until	Execute a set of actions while/until conditions are evaluated TRUE.
useradd	Create a new user or updates default new user information.
userdel	Remove a users account.
usermod	Modify a users account.
vacation	Reply to mail automatically.
vedit	Screen-oriented (visual) display editor based on ex.
vgrind	Grind nice program listings
vi	Screen-oriented (visual) display editor based on ex.
vim	A programmers text editor.
view	A programmers text editor.
w	Show who is logged on and what they are doing.
wait	Await process completion.
wc	Displays a count of lines, words, and characters in a file
whereis	Locate a binary, source, and manual page files for a command.
while	Repetitively execute a set of actions while/until conditions are evaluated TRUE.
which	Locate a command.
who	Displays who is on the system.
whois	Internet user name directory service.
write	Send a message to another user.
X	Execute the X windows system.
xfd	Display all the characters in an X font.
xlsfonts	Server font list displayer for X.
xset	User preference utility for X.
xterm	Terminal emulator for X.
xrdb	X server resource database utility.
yacc	Short for yet another compiler-compiler, yacc is a compiler.
yes	Repeatedly output a line with all specified STRING(s), or 'y'.
yppasswd	Changes network password in the NIS database.
zcat	Compress files.

Difference between AS WS ES and Desktop of Redhat Enterprise linux

here are two Redhat Linux product line, one is free Fedora Core series is mainly used for the desktop version, providing more support for new features. Another product line is the charge Enterprise series, this series is divided into: AS / ES / WS and other branches, they are redhat Enterprise Linux , RHEL for short

AS

Is a super-server version (Advanced Server), Linux kernel in his standard, based on the performance enhancements made, and improved reliability, integrated drivers for many common server. Can easily identify the IBM / DELL / HP rack servers and other common devices such as disk array cards.

AS typical applications are:

1. Databases and database applications

2.WEB and middleware

3.CRM, ERP, SCM

ES

Enterprise server (Enterprise Server), AS the streamlining version. He often is the difference between AS series, AS support to more than 4 CPU, while the ES can only support two CPU. AS and ES in the majority there is no difference on the package, only a small number of packages in the kernel, and so there are differences. AS and ES relatively large difference between the selling price, usually used in the ES together with the server version of purchase such as buying OEM DELL server with the Linux will be the ES series. If you want to with the AS series, you need to spend several thousand dollars.

Typical applications for the ES:

1. Company WEB structure

2. Network edge applications (DHCP, DNS, firewall, etc.)

3. E-mail and file / print services

4. Small and medium-scale database and application software sector

Is the Workstation service version (Workstation Server), ES further simplified version of the main office for enterprise desktop market, the domestic small desktop application using WS is the best environment. It contains a variety of commonly used desktop applications (Office tools, email, instant messaging, browser, etc.), can run a variety of client - server configuration tool, software development tools and various software applications (such as EDA and Oil / Gas Applications , but it does not provide network services (such as DNS and DHCP), it is only suitable for the client application.

AS, ES functionally no different, whether x86, or Itanium version, RHEL's exactly the same after the three disc, that is, exactly the same package. The first disc is actually no packages, just enable the installer to determine the installation package only, but in the service level, the number of supported CPU and memory numbers are different.

Red Hat Enterprise Linux WSRed Hat Enterprise Linux WS (“workstation”) is the highend
desktop/client

member of the Red Hat Enterprise Linux family.
Red Hat Enterprise Linux WS supports 12
CPU 32bit
and 64bit
Intel and
AMD systems (x86, EM64T, Itanium2, and AMD64), and is ideal for “power
user,” software development, and technical applications such as
virtualization/rendering (CAD/CAM, EDA, etc.). It includes a full suite of
desktop productivity applications for tasks such as document creation, email,
instant messaging, and web browsing.
While Red Hat Enterprise Linux WS is based on the same software core as
the server products, it does not include a number of network server
applications (such as DNS and DHCP). Therefore it is suitable only for use in
client environments. Enterprise Linux WS is available with Basic Edition and
Standard Edition support.
HPC with Red Hat Enterprise Linux WS
Red Hat Enterprise Linux WS is usually the most cost effective Enterprise
Linux product for use in High Performance Computing (HPC) environments. In
these environments it is deployed in a headless workstation mode without a
monitor, keyboard or mouse. A few common HPCrelated
packages are
included in the Enterprise Linux family such as PVM and LAM.
Red Hat Desktop
Red Hat Desktop is the highvolume
desktop/client member of the Red Hat
Enterprise Linux family. It supports 32bit
Intel x86 and 64bit
Intel EM64T and
AMD64 systems with one CPU and up to 4 GB of main memory. It provides
the same software functionality as Red Hat Enterprise Linux WS but for
smaller systems and at a lower price point. Red Hat Desktop is provided in
multiunit
packages bundled with a Red Hat Network (RHN) Proxy or Satellite
Server. The RHN server is used to efficiently perform desktop management
functions such as the installation of updates and security patches.