IntroductionSystem administrator tasks

A system administrator is responsible for the following :- Installing and configuring Establishing security enforcements Applying updates and configuration changes Troubleshooting reported errors Performance monitoring and tuning User handling

Activities before putting a server in production such as erection, installation, configuration, hardening, etc will be done by Project Management team.

Activities to maintain the server after handing over to production such as applying updates, troubleshooting, performance issues and user issues are taken care by break-fix or Incident Management team.

Operating system

An operating system is an interface between user and the hardware. A Kernel is the layer of operating system that takes commands from user, converts it as machine understandable form to execute and provide the result in user understandable form.

UNIX flavours

Unix is a multiuser, multitasking operating system.

Unix is a filebased operating system

It was developed initially by AT&T.

IBM, HP and SUN modified unix according to their hardware to provide more robust and reliable system. Unix from different vendors are called as flavours.

HP-UX, Solaris and AIX (Advanced Interactive eXecutive) are the three prominent flavours of UNIX. Other than these SCO (Santa Cruz Operations) unix and LINUX (from Red Hat) are also popular flavours.

Basic UNIX

Tree structure

Unix follows the inverted tree structure. The top level being the root directory having various levels of subdirectories. Files could be added at any level of subdirectory.

/|_ <etc> => startup files|_ <dev> => devices|_ /home => home directories|_ /usr => system files| |_ <bin> => basic commands| |_ <sbin> => admin commands|_ /tmp => temporary filesystem|_ /boot => boot data|_ /paging => virtual memory|_ /var => Maintains log details|_ /opt => Optional filesystem

Directories and files

Unix is case sensitive and all commands should be typed in lowercase.

pwdprint working directory or present working directory, displays the current directory.

mkdir testmake directory, makes a subdirectory with the name test under current directory.

cd testchange directory, changes present directory to test.

cd ..changes the present directory to the parent directory.

cdchanges to home directory.

Absolute and relative path

An absolute path starts with the root directory and a relative path is with reference to present working directory.

cd /usr/binchanges working directory from anywhere in the tree.

cd ../sbinchanges working directory related to the current working directory.

Absolute paths can be used with any command

mkdir /tmp/classcreates a subdirectory class under existing tmp directory.

rmdir /tmp/classremove directory, deletes the directory at the end of the given path. The directory to be removed should be empty. Directory cannot be deleted if it is the current working directory.

lslist, lists the files in the current directory.

ls sam*lists files whose names are starting with sam in the current directory.

ls /homelists files in the directory home.

Options are available for many commands which will modify the output of the command providing additional information. They are also called as flags.

ls –a lists hidden files. Any file starting with a period (.) is a hidden file.

ls –tsorts the list by time with the latest file at the top.

ls –trdisplays the sorted list with the oldest file at the top.

ls –llists in long format. Type, permissions, owner, size, etc., are displayed.Information provided are :-

Type and permissionNo. of linksOwnerGroupFile size in bytesDateTime (year is displayed for older files)Filename

File permissions

The first character of the permission column indicates the type of the file.Heifen (-) indicates a file

d indicates a directoryl indicates a link.

Next nine characters gives the permission, grouped as user, group and others, having 3 charecters in each group.

Characters 2 to 4 gives permission to users (owner of the file)Characters 5 to 7 gives permission to groupCharacters 8 to 10 gives permission to others

Read, write and execute permissions are denoted by presence of r, w and x in the respective positions for each group. Absence of the letter indicates that permission is not given. Permission and ownership could be changed

chmod 764 /opt/newpasschanges the permission of the file as –rwxrw-r--

r =4; w=2; x=1 are the weightages for read, write and execute.

774 is the permission for all 3 groups, digits indiacating the permission for user, group and others respectively.

To give full access of read, write and execute to user 4+2+1=7 is placed as the first digit.

To give read and write access to the group 4+2=6 is placed in the second digit.

Only read access to others is given as the third digit is 4.

chmod g-w,o+x /etc/newpassremoves write permission to group and gives execute permission to others resulting in –rwxr--r-x

cat /etc/passwddisplays the contents of the file passwd in the directory etc. If the file has more number of lines, the screen scrolls and the last part of the file stays in the screen.

pg /etc/passwddisplays the contents of the file, one screen and waits for user to press enter to display the next screen.

more /etc/passwddisplays one screen, and has additional features like scrolling back.

Redirecting output of one command as input to the next command could be done by using the pipe(|) symbol

ls –l | moredisplays the output of the command including the features of the more.

Redirecting output to a file is also possible using the (>) symbol

ls –l > /tmp/liststores the output in the given file instead of displaying in the screen.

head -10 /etc/passwddisplays first 10 lines of the file.

tail -10 /etc/passwddisplays last 10 lines of the file.

cp /etc/passwd /tmp/passwordcopies file passwd to tmp directory with new name.

cp /tmp/password /homecopies file password to the new location with the same name.

mv /home/password /optmoves file password to new location. It is deleted from original location after the completion of the command.

mv /opt/password /opt/newpassrenames a file if specified in the same directory.

ln /opt/newpass /opt/linkpassgives an additional name for the file. The file remains with the new name even if the original is deleted. This is a hardlink and could be used only with files within the same filesystem. Hardlink could not be used with directories.

ln –s /tmp /home/tempcreates a softlink to the directory tmp which could be accessed as a subdirectory of home directory.

rm /opt/newpassdeletes a file.

grep filter

grep is a filter available for pattern matching.

grep system /etc/passwddisplays lines that contains the work system in the given file.

cat /etc/passwd | grep systemresult is same as the above command.

ls –l | grep –i testThe flag is used to ignore case while matching.

vi editor

Command mode : to use alphabets to control the text.Input mode : to type alphabets and characters as part of the text.

Editor will be in command mode when it is started. Esc key is used as prefix before commands. Esc i put vi in input mode and Esc gets back to command mode.

vi /opt/newpass

opens the file in vi editor. If the file does not exist already a blank editor opens and the file will be created by issuing a save command.

:wqSaves file and quits editor.

:w

Saves and continues to be in editor.

:qQuits editor.

:q!Quits editor without saving the changes.

Cursor movementh – leftl – rightk – upj – downw – next wordb – previous word0 – beginning of lineShift + a - end of lineCtrl + f – one screen forwardCtrl + b – one screen backwardShift + h – first lineShift + G – last line

Text insertioni – insert before cursora – insert after cursoro – new line below O – new line above

Text editingcw – change worddw – delete worddd – delete line

Copying and movingyy – copy linedd – cut linep – paste

a number could be added before the above commands to repeat command for that many times. 4yy copies 4 lines. 4dw deletes 4 words.

Processes

A program while running is called as a process. Every process will be assigned a unique number called Process Identifier.

ps displays the list of process running.

ps –efdisplays all processes running in the system with more details.An & should be added at the end of the command to run as a background process. This returns to command prompt as the process continues to run at the background, Whereas the process running at the foreground does not give the command prompt till it completes.

Ctrl + c is used to terminate a foreground process and get back to command prompt. For terminating a background process, its process id should be found and killed using the kill command.

Shells and variables

A shell is a working environment. Depending on the type of usage shell could be provided to users. End user or data entry operator does not need system management commands. They will be using basic commands. System administrators will be using the system management commands.

Bourne shell :- shSimple shell for end user. Displays $ as the prompt.

Korn shell :- kshProvides additional constructs. Displays $ as the prompt

C shell :- cshProvides programming features. Displays % as the prompt

The prompt will be # if the user is logged as root

Changing shells :-Every user is assigned a default shell and will be in that shell on login. This could

be changed by entering sh, ksh or csh in the command line. exit brings back to the previous shell.

The characteristics of a shell are controlled by environment variables.

SHELL – default shell

TERM – terminal type

LOGNAME – login name

HOME – home directory

PS1 – prompt

echo $LOGNAMEdisplays the content of the variable LOGNAME.

Apart from environment variable users can also have their own variables.

cppath = ‘/tmp/test’sets variable cppath and assigns the value to it. This could be used with any command where the assigned value to be used.

echo $cppathdisplays the assigned value.

Variables are local to the shell by default and could not be accesses if the shell is changed. These could be made as global variables if they are exported.

export cppathmakes cppath as a global variable, thus could be accessed in all the shells.

Variables are confined to the current login session only and will not be available for future login sessions. These can be entered in a special file to be executed each time a user logs in.

A file in the home directory of every user is executed everytime the user logs in. That file is the .profile file for bourne and korn shells. If the variable declaration, initialization and export commands are entered in this file, it will be executed on every login and is available without being executed manually.

Root user will have the profile file in the etc directory.

For C shell the home directory will have .login file for users

cron jobs

Commands to be run automatically at the specified time could be submitted to cron. The information will be stored in specific files and will be executed at the mentioned times.

crontab –ldisplays the currently submitted cron jobs.

crontab -eallows to edit the crontab to add or delete jobs. Uses vi editor commands.

Each line in the crontab is a separate job. The line should begin with the date and time details in 5 columns.

minute hour date month day command0-59 0-23 0-31 1-12 0-7

* in any column indicates all possible values.Distinct values or range could also be given.The jobs submitted are stored in a file with the username as the filename in /var/spool/cron/crontabs.

/var/adm/cron/cron.allow file contains usernames who are allowed to submit cron jobs. All other users are denied.

/var/adm/cron/cron.deny file contains usernames who are denied to submit cron jobs. All other users are allowed.

Pseries and AIX introduction

Classification of microprocessors

Complex instruction set computers (CISC) and Reduced Instruction set computers (RISC) are two classification of computers based on the number of instructions that could be executed.

RISC system has fewer instructions and are faster and reliable.

IBM system series

IBM has the following series of systems

x series – intel based systems

z series – Mainframe systems

i series – AS/400 systems

p series – RISC systems

P series evolution

IBM introduced RISC System (RS/6000) in 1986.

Performance Optimized With Enhanced Risc (POWER) system was introduced in 1990. Which was the starting of the pseries.

Power 2 was introduced in 1993 and power 3 in 1999.

New naming as eserver pseries was given on 2000 and power 4 was introduced.

Regatta was introduced in 2001 which included LPARs.

Models : p690, p670, p650, p595, p570, 7026 -6H1, 7017-S85, H80, 7028, 7013-59H, 7038

Power 5 : p510,p520,p550,p570, p575, p590, p595

Power 4 : p615,p630,p650,p670,p655,p690

AIX versions

AIX was introduced even before the pseries during the initial RS/6000 days in 1986.

The initial version is 1.3

Version 3.0 was introduced in 1990 which included LVM and SMIT.

Version 3.1 introduced Journalled File System (JFS)

Version 4.2 in april 1997 supported nfs3

Version 4.3 provided support for 64 bit architecture and online backup

Version 5.1 in May,2001 is the minimum level for power4 systems. 64 bit kernel, jfs2 and LPAR are introduced.

Version 5.2 introduced mpio fiber channel, DLPAR and is the minimum level for power5 systems.

Version 5.3 is the current AIX version and includes VIO and micro partitioning, and filesystem shrink.

OS Installation

Installation types

New and Complete Overwrite- Done on a new machine- Done when rootvg is corrupted

Migration- Done for upgrading OS version- /tmp is overwritten

Preservation- Preserves only user data- /usr, /tmp, /var, / are overwritten (recreated)- /etc/preserve.list contains a list to be preserved

Trusted Computing BaseIt enforces information securityIt monitors every file in the /dev directoryIt also monitors 600 other files which are listed in /etc/security/sysck.cfgIt can be enabled only during installation/usr/bin/tcbck displays usage if it is enabled.

Installation methods [NIM, alt_disk_install]

AIX comes in CDs and can be installed using CD ROM.

NIM(Network Install Management) facilitates installtion using a network source, avoiding human assistance at the server location. This can be accomplished from remote location. The installable resources will be created on a NIM master and the NIM client can be installed with AIX operating system.

Alt_disk_install is a method used during OS migration. The mirror will be broken and the new version will be installed in one of the disks. The system will be available during the time with the existing version. After installation on one of the disk, the system will be booted with that disk and tested. If everything is fine the old version can be removed. If the new version gives some issues, old version can be used.

ODM and device configuration

Objects and Classes

The basic components of ODM are object classes and objects. Object - an entity that requires storage and management of dataobject class - A group of objects with the same definition Object Descriptors - Variable name with type

Disk is a class, which defines some the characteristics any disk should possess.

A physical harddisk is Object Data Manager

System data managed by ODM includes: Network configuration Logical volume management configuration Installed software information Devices that AIX has drivers for

Logical devices or software drivers Physical hardware device installed Menus, screens and commands that SMIT uses

Location of ODM/etc/objrepos - Main location for the ODM/usr/lib/objrepos - /usr/share/lib/objrepos

This settings is in - > /etc/environmentODMDIR = /etc/objrepos

Types of Databases – predefined and customizedPredefined database - > PdDvDevices that are supported but not currently installed/usr/lib/objrepos

Customized Database - > CuDvDevices found and configured/etc/objreposODM commandsodmadd - Add an object to classodmchange - to change a specfefic object in aclass odmdelete - to delete an object

odmcreate - > created an empty object classodmdrop - delete a odm object classodmget - list the objects in the obj classodmshow - list the properities of the odb class

Device status – Available and definedAvailable – users can access the deviceDefined – Device available in ODM, users cannot access

Handling devices – list, change, remove, makelsdev - displays device and charecteristicslscfg - displays configurationlsattr - displays attributes with values

cdcux57:root:/>lsdev -l ent0ent0 Available 20-70 IBM 10/100 Mbps Ethernet PCI Adapter (23100020)

cdcux57:root:/>lscfg -vl ent0 ent0 U0.1-P1-I4/E1 IBM 10/100 Mbps Ethernet PCI Adapter (23100020)

Serial Number...............02092195 FRU Number..................091H0397 Part Number.................091H0397 Network Address.............0004AC5ED4A3 Displayable Message.........PCI Ethernet Adapter (23100020) Device Specific.(YL)........U0.1-P1-I4/E1

cdcux57:root:/>lsattr -El ent0alt_addr 0x000000000000 ALTERNATE ETHERNET address Truebusintr 25 Bus interrupt level Falsebusio 0x7ff800 Bus I/O address Falsefast_reset yes Enable Fast Reset Trueintr_priority 3 Interrupt priority Falseip_gap 96 Inter-Packet Gap Truemcast_filter no Enable Multicast Filtering Truemedia_speed 100_Full_Duplex Media Speed Truepoll_link no Enable Link Polling Truepoll_link_timer 500 Time interval for Link Polling Truerx_hog 1000 RX buffers processed per RX interrupt Truerx_que_size 256 RECEIVE queue size Truerxbuf_pool_size 384 RECEIVE buffer pool size Trueslih_hog 10 Interrupt events processed per interrupt Truetx_que_size 8192 TRANSMIT queue size Trueuse_alt_addr no Enable ALTERNATE ETHERNET address Truecdcux57:root:/>

Changing a deviceThe attributes given as True can be changed by using chdev command.

chdev –l ent0 –a media_speed=auto

Removing a device

rmdev –l ent0

The above command will remove the device from usage and take it defined state. The device is still available on the ODM.

rmdev –dl ent0

The –d flag will remove the device from ODM and thus completely removing from the system. To physically remove a device, this option should be used.

Configuring devices – cfgmgr, mkdev

A device in defined state can be brought back as available because ODM has its information.

mkdev –l ent0

A device removed from ODM or a new device connected to the system can be configured by the following.

cfgmgr

This will configure and make the device available.

Some devices

sys0 – entire systemsysplanar0 – system boardent0 – Ethernet cardmem0 - memoryhdisk0 – hard diskrmt0 – tape drivefcs0 – fiber adapteride0 – IDE I/O adapterscsi0 – SCSI adapterproc0 – Processor

The first device of a type will have 0 as suffix to the name and the consecutive devices of the same type will get 1,2,3 and so on.

System Resource Controller

http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.baseadmn/doc/baseadmndita/sysrescon.htm

The SRC provides a single set of commands to start, stop, trace, refresh, and query the status of a subsystem

The System Resource Controller (SRC) is started during system initialization with a record for the /usr/sbin/srcmstr daemon in the /etc/inittab file.

Daemon

A process running continuously at the background to provide an additional feature or perform an activity of an operating system.

Subsystem and subserver

A subsystem is any program or process or set of programs or processes that is usually capable of operating independently or with a controlling system. A subsystem is designed as a unit to provide a designated function

A subsystem as a program or set of related programs designed as a unit to perform related functions

A subserver, commonly known to UNIX programmers as a daemon, is a process that belongs to and is controlled by a subsystem

The System Resource Controller hierarchy begins with the operating system followed by a subsystem group (such as tcpip), which contains a subsystem (such as the inetd daemon), which in turn can own several subservers (such as the ftp daemon and the finger command).

SRC – list, start, stop and refresh

dupprt04:/>lssrc -g tcpipSubsystem Group PID Status xntpd tcpip 286934 active snmpd tcpip 282808 active hostmibd tcpip 295114 active snmpmibd tcpip 299208 active aixmibd tcpip 311500 active muxatmd tcpip 258216 active inetd tcpip 504020 active

dupprt04:/>lssrc -g nfsSubsystem Group PID Status biod nfs 266428 active nfsd nfs 233644 active rpc.mountd nfs 135310 active rpc.statd nfs 315582 active rpc.lockd nfs 307372 active nfsrgyd nfs inoperative gssd nfs inoperative

dupprt04:/>lssrc -g spooler Subsystem Group PID Status qdaemon spooler 225462 active writesrv spooler 291008 active lpd spooler 168140 activedupprt04:/>

lssrc –s inetd [lists the information about inetd subsystem

lssrc –t ftp [lists the information about ftp subserver

startsrcstopsrcrefresh

-s for sybsystem-t for subserver-g for group

Software Installation

http://www.ibm.com/developerworks/aix/library/au-dutta_work.html

Filesets – It is a smallest unit of installationPackage and LPP

Package is a set of related filesets.LPP(licensed program package) is a group of related packages and filesets.

APAR and PTFProgram Temporary Fix is an immediate solution to a reported problem. A report is associated a Problem Management Report(PMR) number. An Authorized Program Analysis Report (APAR) associates a fix to a PMR. APARs will be assigned a unique number like IY18782

Maintenance and Technology levelsA Maintenance Level (ML) is the service updates that are necessary to upgrade the base operating system (BOS) or an optional software product to the current release level.

Starting in 2006, as part of the new AIX 5L Service Strategy, MLs are replaced by Technology Levels (TLs). They are defined below.

Technology Level A Technology Level (TL) is the new term for the twice yearly AIX 5L releases, which contain new hardware and software features and service updates. The first TL will be restricted to hardware features and enablement, as well as software service. The second TL will include hardware features and enablement, software service, and new software features.Installing a TL should be viewed as an "all or nothing" operation, meaning that requisites will be added so that the whole TL is installed, and not allow a TL to be partially installed. You should back up your system prior to installing a TL.

Service Pack A Service Pack (SP) consists of service-only updates (also known as PTF's) that are released between Technology Levels to be grouped together for easier identification. These fixes address highly pervasive, critical, or security-related issues. Service Packs are provided for the N and N-1 releases (for example, V5.3 and V5.2) on the latest Technology Level for each release (for example, 5300-04 and 5200-08).

Concluding Service Pack Concluding Service Pack (CSP) is the last Service Pack for a Technology Level. The CSP contains fixes for highly pervasive, critical, or security-related issues just like a Service Pack, but it might also contain fixes from the newly released Technology Level that fall into these categories. Therefore, a CSP contains a very small subset of service that was just released as a part of a new Technology Level.CSPs allow for extended service on a Technology Level through the utilization of Interim Fixes.

Interim Fix The term Interim Fix is used as a replacement for "emergency fix" or "efix". While the term emergency fix is still applicable in some situations (a fix given in the middle of the night

with minimal testing), the term Interim Fix is more descriptive in that it implies a temporary state until an update can be applied that has been through more extensive testing.

Applied Vs CommittedAn installed fileset can either be in applied or committed state. A new version of a fileset will be put in applied state. The existing version will be maintained in the system and the new version will be used. If the applied version does not perform well it can be rejected and the previous version maintained at the system will be put back in use. If the new version is found to be perfect, it will be committed.

Table of contents

Installable files will be of backup file format(.bff)The directory that contains the bff files should also have table of contents file .tocIf bff files are copied to a directory the .toc can be created by the commandinutoc <directorypath>

instfix, installp and lppchk

installp is the command used to install filesets, ml and tl.

instfix is the command used to install fixes and APARs

installp –c to commit an applied versioninstallp –r to reject an applied versioninstallp –u to uninstall committed filesetlslpp –l to list all the installed filesets and packageslslpp –h to display the fileset history with dates

instfix -k IY69289 -d /dev/cd0 to install APAR from the cd.instfix –i to list all the installed APARsinstfix -ik IY69289 to check whether the APAR is installedinstfix –i | grep ML to check all APARs are up to date to current ML.

lppchk –v to check for software consistency. This will report the broken fileset(improperly installed) .

installp –C will cleanup the broken filesets.

Vital Product Datalpp(description and status) – displayed in lslppproduct(prerequisites) – base requirementhistory(updates) – version wise historyinventory(files) – actual files.

A software consists of three parts

/usr contains the part that can be shared with other systems having the same hardware configuration.

/ contains the part that are individual for the installed system

/usr/share contains part that can be shared with any system

Logical Volume ManagerConcepts – PV,PP,VG,LV,LP and FSDefault LVsQuoram – VGDA, VGSA, LVCBJournalled File SystemPaging space – list, add and removeVG operations – mirroring, extending, reducing, syncvg and exportingLV operations – create, copy, extend and removeFS operations – create, increase, remove, mount and unmountSpace commands – df and duSysdump and nfs

Boot ProcessLoading the operating system in memory is called as booting. AIX

systems carries out booting in three phases.

Phase 1: - Configures base devicesPhase 2 :- rootvg is brought onlinePhase 3 :- All devices and vgs are setup

The initial step in booting a system is the Power On Self Test (POST). Its purpose is to verify that the basic hardware is in a functional state. The memory, keyboard, communication, and audio devices are also initialized

System Read Only Storage (ROS) will locate and load bootstrap code. Software ROS (also named bootstrap) forms an IPL control block, takes control and builds specific boot information.

A special file system located in memory and named the RAMFS file system is created.

Software ROS then locates, loads, and turns control over to the boot logical volume (BLV).

A complete list of files that are part of the BLV can be obtained from the /usr/lib/boot directory.

The most important components are the following:– The kernel– Boot commands called during the boot process, such as bootinfo andcfgmgr– A reduced version of the ODM. Many devices need to be configuredbefore hd4 is made available, so their corresponding methods have to bestored in the BLV.– The rc.boot script

The kernel is loaded and takes control. The kernel will complete the boot process by configuring devices and starting the init process.

So far, the system has tested the hardware, found a BLV, created the RAMFS, and started the init process from the BLV. The rootvg has not yet been activated. From now on, the rc.boot script will be called three times, and is passed a different parameter each time.

Phase 1

The init process started from RAMFS executes the boot script rc.boot 1

The restbase command is called to copy a partial image of ODM from the BLV into the RAMFS.

Base devices are all devices that are necessary to access rootvg. cfgmgr –f configures the base devices.

The bootinfo -b command is called to determine the last boot device.

Phase 2

The rc.boot script is passed to the parameter 2 as rc.boot 2

The rootvg volume group is varied on with the ipl_varyon command.

Root file system hd4 is checked using the fsck -f command. This will verify whether the file system was unmounted cleanly before the last shutdown.

The root file system (/dev/hd4) is mounted on a temporary mount point (/mnt) in RAMFS.

The /usr file system is verified using the fsck -f command and then mounted.The /var file system is verified using the fsck -f command and then mounted.

The copycore command checks if a dump occurred. If it did, it is copied from default dump devices, /dev/hd6, to the default copy directory, /var/adm/ras. Afterwards, /var is unmounted.

The primary paging space from rootvg, /dev/hd6, will be activated.

The mergedev process is called and all /dev files from the RAM file system are copied onto disk.

All customized ODM files from the RAM file system are copied to disk. Both ODM versions from hd4 and hd5 are now synchronized.

The root file system from rootvg (disk) is mounted over the root file system from the RAMFS. The mount points for the rootvg file systems become available.

The /var and /usr file systems from the rootvg are mounted again on their ordinary mount points.

rootvg is activated.

Phase 3

/etc/init process is started. It reads the /etc/inittab file and calls rc.boot with argument 3.

The /tmp file system is mounted.

rootvg is synchronized by calling the syncvg command.

The cfgmgr command is called to configure all other devices that are not base devices.

The console is configured by calling the cfgcon command. After the configuration of the console, boot messages are sent to the console. Before this, all boot messages will be copied to alog. The alog command maintains and manages logs.

The synchronization of the ODM in the BLV with the ODM from the / (root) file system is done by the savebase command.

The syncd daemon and errdemon are started.

The LED display is turned off.

If the file /etc/nologin exists, it will be removed. This file, if exist, will prevent users other than root from logging into the system. The contents of this file will be displayed as a message for users other than root.

The execution of rc.boot is has completed. Process init will continue processing the next command from /etc/inittab.

NetworkingIP address – notation used to identify a network resourceinetd daemon

inetd daemon provides internet service mgmt, invokes other related deamons only when needed.

/etc/inetd.conf file specifies the subservers(ftpd, telnetd, etc) controlled by inetd.

/etc/services file specifies the port at which the subserver provides its service.

commands – ifconfig, entstat, ping, traceroute, netstat, route

Every network adapter will have a corresponding interface.

ifconfig command configures or displays network interface parameters.

ifconfig –adisplay information about all interfaces in the system.

ifconfig en0 192.168.5.25 alias adds an address to interface en0

ifconfig en0 192.168.5.25 deleteremoves the specified address from en0

ifconfig en0 detach

removes network card from the interface list.

mktcpip sets values for tcpip

mktcpip -h hostname -a 192.9.200.4 -i en0 -n 192.9.200.1

entstat –d ent0 displays the statistics of the device. Details about collisions, MAC address, etc., will be displayed. The link status and connection speed are also given.

netstat displays the state of all configured interfaces(/)> netstat -iName Mtu Network Address Ipkts Ierrs Opkts Oerrs Collen0 1500 link#2 0.60.94.e9.8b.9d 39476281 0 55159681 0 0en0 1500 52.99.9 asdux02i 39476281 0 55159681 0 0en1 1500 link#3 0.6.29.6c.88.d3 247102188 0 243097048 0 0en1 1500 153.116.242 asdux02 247102188 0 243097048 0 0en2 1500 link#4 0.6.29.6c.b0.2d 310281117 0 1701 0 0en2 1500 153.116.243 asdux02-bu 310281117 0 1701 0 0css0 65504 link#5 36326212 0 37558194 0 0css0 65504 52.99.8 asdux02s 36326212 0 37558194 0 0lo0 16896 link#1 61901228 0 61928648 0 0lo0 16896 127 loopback 61901228 0 61928648 0 0lo0 16896 ::1 61901228 0 61928648 0 0root@[asdux02]:

(/)> netstat -niName Mtu Network Address Ipkts Ierrs Opkts Oerrs Collen0 1500 link#2 0.60.94.e9.8b.9d 39476292 0 55159690 0 0en0 1500 52.99.9 52.99.9.17 39476292 0 55159690 0 0en1 1500 link#3 0.6.29.6c.88.d3 247102225 0 243097081 0 0en1 1500 153.116.242 153.116.242.32 247102225 0 243097081 0 0en2 1500 link#4 0.6.29.6c.b0.2d 310281190 0 1701 0 0en2 1500 153.116.243 153.116.243.63 310281190 0 1701 0 0css0 65504 link#5 36326222 0 37558203 0 0css0 65504 52.99.8 52.99.8.17 36326222 0 37558203 0 0lo0 16896 link#1 61901237 0 61928657 0 0lo0 16896 127 127.0.0.1 61901237 0 61928657 0 0lo0 16896 ::1 61901237 0 61928657 0 0root@[asdux02]:(/)>

netstat –r gives the routing table.(/)> netstat -nrRouting tablesDestination Gateway Flags Refs Use If PMTU Exp Groups

Route Tree for Protocol Family 2 (Internet):default 153.116.242.1 UG 9 27923861 en1 - - -52.99.4/24 52.99.8.250 UG 0 0 css0 - - -

route command is used to manipulate the routing table.

route add default 192.168.5.25adds another default gateway

route delete default 192.168.5.25removes the IP address from being a default gateway.

route add 192.100.201.7 192.100.13.7Packets reaching 192.100.13.7 will be sent to host with address 192.100.201.7 .

route add -net 192.100.201.0 192.100.13.7Packets reaching 192.100.13.7 will be sent to any host on the destination network.

route –fclears the routing table.

ping command is used to check end to end communication.

traceroute command is used to check the hops of the packet.

sendmail – sendmail.cf

Sendmail daemon provides means to send and receive mails and reads /etc/sendmail.cf file.

sendmail sparthasarat@csc.com < /etc/motdsends the contents of the file as mail body

uuencode /etc/motd newname | mail -s "test mail" sparthasarat@csc.comsends the file as an attachment with given name.

Nameserver – resolv.conf

Lookup – Finding the IP address of device based on the hostnameReverse Lookup – finding the hostname based on given IP address./etc/hosts file will contain IP address and hostnames and a IP can be fetched for a

given hostname from this file.

The hostname and IP addresses can also be made available on a DNS server where the lookup is performed when it is not available in the /etc/hosts file. The DNS server information is stored in /etc/resolv.conf file.

The lookup order can be changed by making appropriate entry in /etc/netsvc.conf file.

hosts=local,bindthis entry will first search the /etc/hosts file and then the DNS

Backup and RestorationSystem backup - mksysb Tape control – tctlBackup strategies – Full, Differential, IncrementalVG Backup – savevg and restvgFile Backup – backup and restoreCompressions – tar and gzip

Error handlingerrdemon is started during boot and will serve to capture and report errors.Errors will be stored in /var/adm/ras/errlog file.errpt fetches information and displays in readable format.

(/)> errpt | moreIDENTIFIER TIMESTAMP T C RESOURCE_NAME DESCRIPTIONAA8AB241 0726050107 T O OPERATOR OPERATOR NOTIFICATIONBD797922 0726010007 P H enclosure1 SUBSYSTEM FAILUREBD797922 0726000007 P H enclosure1 SUBSYSTEM FAILUREBD797922 0725230007 P H enclosure1 SUBSYSTEM FAILUREBD797922 0725220007 P H enclosure1 SUBSYSTEM FAILURE

First column is a label. Second column is timestamp in the format MMDDhhmmYY. Third column tells the severity as P for permant, T for temporary errors and I for information. Fourth column shows the type of the resource as S for software, H for hardware. Fifth column gives the resource name and the last column gives the error description.

errpt –j BD797922 displays only errors with the given label

errpt –a displays detailed report about all errors.

errpt –aj BD797922 displays detailed report about the given label.

(/)> errpt -aj BEE2FB4A | more---------------------------------------------------------------------------LABEL: TS_DEATH_TRIDENTIFIER: BEE2FB4A

Date/Time: Wed Jun 5 20:04:03 DFTSequence Number: 69138Machine Id: 000219844C00Node Id: tsdux41Class: UType: UNKNResource Name: hats.tsdcw01Resource Class: NONE

Resource Type: NONELocation: NONEVPD:

DescriptionContact with a neighboring adapter lost

Probable CausesThe neighboring adapter mal-functionedNetworking problem renders neighboring adapter unreachable

Failure CausesThe neighboring adapter mal-functionedProblem with the network

Recommended Actions Verify status of the faulty adapter Verify status of network

Detail DataDETECTING MODULErsct,threephs.C, 1.135.1.11,3944ERROR ID.8hjsyyH8Zzw.LwI1dYkMo....................REFERENCE CODE

The IP address of the faulty adapter52.99.8.42Node number where the adapter is located 7

errclear clears the errors from errlog

errclear 0clears all errors.

errclear 5removes errors before 5 days

errclear –d S 0removes software errors

errclear –T PERM 0 removes permanent errors

errlogger is used to log operator messages.

errlogger “test error message”puts and operator notification.

Performance Monitoringvmstat

iostatsarsvmontopasTuning - vmo, no and vmtune

Print Queue ManagementCreating print queue – smitty queueChecking status – lpstat -aPrinting a file – lp -dqdaemon

User AdministrationPassword and group filesCommands – lsuser, mkuser, passwd, rmuserEnvironment and limits

Miscellaneous commandsprtconfunamebootinfobootlistbindprocessor

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