AIX is short for Advanced Interactive eXecutive. AIX is the UNIX operating system from IBM for RS/6000, pSeries and the latest p5 & p5+ systems. Currently, it is called "System P". AIX/5L the 5L addition to AIX stands for version 5 and Linux affinity. AIX and RS/6000 was released on the 14th of February, 1990 in London. Currently, the latest release of AIX is version 6. AIX 7 beta will be released in Aug 2010, along with the new POWER7 hardware range.
Multi-platform UNIX systems consultant and administrator in mutualized and virtualized environments
I have 4.5+ years experience in AIX system Administration field. This site will be helpful for system administrator in their day to day activities.Your comments on posts are welcome.This blog is all about IBM AIX Unix flavour. This blog will be used by System admins who will be using AIX in their work life. It can also be used for those newbies who want to get certifications in AIX Administration. This blog will be updated frequently to help the system admins and other new learners. DISCLAIMER: Please note that blog owner takes no responsibility of any kind for any type of data loss or damage by trying any of the command/method mentioned in this blog. You may use the commands/method/scripts on your own responsibility.
If you find something useful, a comment would be appreciated to let other viewers also know that the solution/method work(ed) for you.
Q. To show which filesets need to be installed or corrected ?
A. lppchk -v
Q. how to fix if a vg is corrupted?
A. for rootvg use redefinevg -d hdisk0 rootvg
For
non-roorvg use import and export
For PV
use syncvg -p hdisk2 hdisk3
To all
PV in VG use syncvg -v testvg
For LV
use reorgvg testvg lv1 lv2
For FS
use fsck -y /dev/lvname
Q. Howto
replace a disk?
A. extendvg testvg
migratepv
reducevg
-d testvg
Q. How can I clone the rootvg?
A. alt_disk_copy -d hdisk1
(from 5.3 onwards alt_disk_install is devided into
alt_disk_copy, alt_disk_mksysb and alt_disk_op )
Q. How many processors does my system have?
A. lscfg |grep proc
bindprocessor -q
lsdev
-Cc processor
Q. How can I determine which fileset updates are missing
from 6100-10 ?
A. #oslevel -rl 6100-10
Q. How do I mount a cd?
A. mount -v cdrfs -o rw /dev/cd0 /cdrom
Q. How do I display information about installed filesets
on my system?
A. #lslpp -l
Q. How to check whether the APAR is installed or not?
A. #instfix -ik ( here apar's are started
with IV,IZ &IY73748)
Q. How to set non-expiry password in AIX?
A. #pwdadm -C
Q. What is /etc/inittab?
A. It contains the startup sequence of all processes,
fields are PID,Runlevel,Action and command
Q. What is the first process to start on a UNIX system, after
the kernel?
A. init
Q. What is an inode?
A. i-node
(index node)
A file system has a fixed number of i-nodes that are located following the
superblock. i-nodes contain information about files, including the location of
the data on the disk. They contain all of the identifying information about
files (file type, size, permissions, user/group/owner, create/modification and
last access dates) except for the file name, which is stored in the directory,
and the contents of the file, which are stored in the data blocks. Each file or
directory has an i-node associated with it. AIX reserves a number of i-nodes
for files and directories every time a file system is created, and if all the
available inodes are used, no more files can be created, even if the fs has
free space.
Q.
What is superblock ? how to
recover superblock ?
A. Superblock
In a JFS, the superblock is the first addressable block (and a backup at the
thirty-first addressable block) on a file system. It is 4096 bytes in size. The
superblock is very important because a file system cannot be mounted if the
superblock is corrupted. This is why there is a secondary or backup superblock
at block 31. The superblock contains the following: size of the filesystem,
number of datablocks in the fs, state of the fs...
Q. What is the Changed time on an
inode/file mean?
A.
Last time the inode was modified
Q. What’s an indirect block?
A.
Pointer to a list of blocks
Q. What is RAID?
A. Redundant Array of Independant Disks, striping,
mirroring, and Stripping with parity etc..
Q. How do I change the priority of a process?
A. renice -n 5 -p
nice
-n 15 WE can use from 0-39
Thenicecommand runs another
command at a different priority, while therenicecommand changes the
priority of an already running process
Q. How
do u find the fix is installed?
A. Lslpp -l
instfix
-i| grep ML
Q.
Attributes of FS?
A. File size, date,owner,name etc.....
##Q.
List all the LV in system?
A. lslv -L
Q. Why is the . not included in the path ?
A. the
dot is not supposed to be in your path because when you enter a command, your
environment i.e. your path will try and execute from your pwd which is never a
good thing.
Q. A system is echoing the ping but not able to login via telnet
why ?
A. edit /etc /services & /etc/inetd.conf
Telnet daemon is down and telnet service is not active
Q. How
to migrate 5.3 to 6.1 ? (or any versions)
A. Migration insttalation using NIM or AIX CD.
Q. A
system is able to ping within the network but not outside why ?
A. default gateway is not defined or not cofigured properly
Q.
What are the components of a HACMP ? (did you use serial interface)
A. - Nodes
- Networks
- Sites
- Topology
- Resource Groups
- RSCT components (group services, topology services and
RMC)
- Events and Notifications
- Recovery scripts
Q. How to Upgrade a cluster, if you have deployed PowerHA
SystemMirror 7.1 or Cluster Aware AIX in your AIX environment ?
A. If you are usingPowerHA SystemMirror 7.1:
1. Backup the cluster configuration using the PowerHA
SystemMirror snapshot facility
2. Stop the PowerHA 7.1.0 Cluster Services through SMIT.
Select the entire list of nodes names to stop cluster services on all nodes in
the cluster: (smitty hacmp -> System Management(CSPOC) -> PowerHA System
Mirror Services -> Stop Cluster Services).
3. Remove the CAA cluster using the AIX command rmcluster
(syntax: rmcluster –n clusterName) on one of the nodes in the cluster.
4. Install the desired AIX Level (6100-07 or 7100-01 or
later AIX Technology Level) on all nodes. Note that this step will also install
the latest level of RSCT.
5. Note that reboot would be necessary after the update of
the AIX TL level.
6. Verify to make sure that the AIX and RSCT levels are the
following:
a. AIX 6100-07 or 7100-01 or higher
b. RSCT Level 3.1.2.0 or higher
7. Recreate the CAA cluster from PowerHA SystemMirror:
(smitty hacmp -> Cluster Nodes and Networks -> Verify and Synchronize the
cluster configuration)
8.Restart the
PowerHA SystemMirror 7.1 Cluster: (smitty hacmp -> System Management (CSPOC)
-> PowerHA System Mirror Services -> Start Cluster Services).
If you are usingCluster Aware AIX:
1. Note down the CAA cluster configuration information.
2. Remove the CAA cluster using the AIX command rmcluster.
3. Install the desired 2011 AIX Technology Level
(6100-07/7100-01) or later AIX
releases on all nodes. Reboot the node as necessary.
4. Redeploy the CAA cluster using mkcluster command.
Q. What are the resource groups in HACMP?
A. Rotating, cascading and mutual takeover
Q. What are the apar install if so for what ?
A. Apar is interim fix for fixing identified issues between the release of
various SP levels. SP level is often consists of collection of various apars.
check for installed apar using command "instfix -ik
Q. How will you log in or start the system if u don't know the
root password?
A. boot in maintanance mode and set the root password
Q. What is ip address and subnet means ?
A. internet protocol address is used to communicate wit other devices in the
network, subnet mask is used to identify the network address of an ip address
Q. how will you check, if a system is paging excessively ?
A. check the configured paging space and its usage using command "lsps
-a"
- Check the the snapshot of system resource usage using
command "topaS"
- check detailed paging space utilization using command
"vmstat"
Q. There is too much of processor utilization what could be
possible reason?
A. too much processor utilization could be because of defunct processes,
respawning process and high processor utilizing applications.
Q. How is paging space is allocated?
A. It is allocated in form of a paging LV configured either on a rootvg,
secondary devices or both
Q. How will you assign superuser privilege to an ordinary user
temporarily (sudo)
A. RBAC is introduced in AIX 6.1
Q. Based on what one will choose to use shell or perl scripting
?
A.Some complex functions cannot be executed with generic shell so a special
program code is used in another language which could be perl.
Q. Difference between telnet or ssh .
A. ssh is secure shell using a secure shell protocol where as telnet provides
unsecured communication
ssh
could be configured as a server/client, but it is not possible with telnet
Q. How will you truncate a log file ?
A. To truncate a file we need to be nullify that means #cp
/dev/null
What is a sticky bit what is the effect on file and directory ?
A. Stickybit is used set the permissions of a user. If u
set sticky bit then that user and the super user only can rename and delete the
file or dir
chmod +t To add sticky bit
chmod -t To remove sticky bit
chmod g+s to set SGID
chmod u+s To set SUID
Q. How to check Broken filesets?
A.lppchk -v
Q. What is ur ticketing agent?
A.Maximo
Q. How to check all FS’s in a vg?
A. lsvg –l
##Q.How to find Which LV is mapped to which PV?
A. lslv –m
Q. Which LV is not mounted at the system boot?
A. boot , paging , raw
##Q. What is the extension for snapshot?how to take
snapshot?
A. # snap -r
# snap -ac
#cd /tmp/ibmsupt
# mv snap.pax.Z pmr#.branch#.000.snap.pax.Z
dowload to local machine, go to command prompt
ftp testcase.software.ibm.com
login as user 'anonymous' with your email address for the
password
ftp> cd /toibm/aix
ftp> bin
ftp> hash
ftp> put pmr#.branch#.000.snap.pax.Z
ftp> bye
Q. How to change the priority of the
process?
A.nice -- command
Q. How to check Errors ?
A.Using alog and errpt
(errpt –a –j For detaild view )
Q. How to install a fix and a software?
A.instfix and installp
Instfix – to install the fixes that extension with IZ
(IX38794) ; instfix –k -d
Installp – to install the filesets
Emgr –P –e (For preview)
Emgr –X –e (for installation)
--> Q. How to clear the failed filesets?
A. lslpp –C
Q. How to replace physical volume in hacmp? (From sharedvg
while online)
First take the backup of that disk and inform to all
client, which are login by server.
Use smitty hacmp -> C-SPOC -> HACMP physical volume
management -> Add a source disk -> add a destination disk.
Q. How will you replace falling disk
mirrored rootvg?
ounmirrorvg rootvg diskname
ochpv –c faileddiskname
oreducevg rootvg diskname
ormdev –dl diskname
oAdd new disk and configure using
cfgmgr
oextendvg rootvg diskname
omirrorvg rootvg diskname
osyncvg –v rootvg
obosboot –ad /dev/diskname
oSet bootlist
Q. Difference between AIX5.1, 5.2 and
5.3?
oAIX 5.1 Jfs2 file system is
introduced
oSupport both uni and multiprocessor.
oAIX 5.2 DLPAR
oSystem scalablity
oJfs2 file system upto 16TB
oDuoD-Dyanamic capacity upgrade on
demand
oAIX5.3 Scalable vg introduced
oSupport only multiprocessor kernel
oDLPAR
oWorkload management
oVariable Logical Track Group size
oShrink file system support
oDump procedure is enhanced to use
nvram to store minimal dump info.
oAIX 6.1 turning off jfs2 logging to
increase performance
orm command & variable LTG(Logical
Track Group)
onew security enhancements & OS is
installed with minimal services, allowing you to activate only the additional
features that you actually need
oRBAC is added
oWPAR
oEnhanced Virtualization,Live
Partition mobility
Q. What is the stanza of lsvg –l
rootvg?
Lvname,
type, lp, pp, pv, lvstate, mount point
Q. What is the procedure to configure
LPAR?
Typically all partition creation and management is
performed through the H/W(HMC). The CLI is an advanced option and still
requires an HMC.
TASK No Description Comment.
Start the partition wizard
Partition name ID and type
Workload management participation
Partition profile name
Partition profile memory values
Partition profile processor value
Partition profile interactive value (if available)
Allocation of physical I/O resources
Allocation of virtual I/O resources.
Q. What is the stanza of /etc/security/login.cfg?
It contained parameter related login info like
logintimes,loginreenable, logindelay, logindiabled etc.
Q. What is /etc/security/limit?
It contained resource limit a user can use. Resources like
no of CPU, amount of RAM, size of file etc.
Q. What are the major problems you are attended In your
setup?
Generally I faced file system full, performace problem,
booting problem, and network problem, disk failure, Ethernet adapter failure,
memory problem, and loose connection of cables.
Q. If the user login, the system is very slow, what steps
you will follow?
Entry is available in /etc/nologin for that user, root
should remove this entry then only user can login.
Q. What is the snap and its. Output directory?
Snap is used to format dump o/p and send to IBM.
/tmp/ibmsupt/genral
Q. In production environment what is the procedure to down
the application?
Inform team leader and IT head and take permission. Inform
all users to logout, who is login.
We used in commercial tax
First shutdown report server by stopping service
Second shutdown application server by stopping service.
Then shutdown oracle database server then if necessary
power of all machine.
Q. umask value for security references?
022
Q. How to change the PP size, which already exists VG? Is
it possible? Tell the procedure?
Change pp size by opening vi /image.data
Create mksysb using I option
Then restore mksysb
Q. If user complaint that the system is very slow, what
step you will follow?
Check where the system resources is overloaded by
performance tool.
Kill that process, which are using more resources with the
consultation with team leader & IT head. And inform all the users who is
login?
Q. how to find the selected device is bootable or not?
A.ipl_varyon -i
Q.How to check the processor type?
lsattr -El proc0 -a type
lscfg -vps -l proc0
Q.is a non-root user needs to be able to create users,
change passwords ?
In AIX 5.3, RBAC (Role Based Access Control) is not
available. It's available only from AIX 6.1.
Q. How to Move all LV's in a PV which was damaged?
Q. How to check the power supply is hot swappable or not?
#lsslot
Q. How
would I know if my System p machine (hardware) is 32-bit or 64-bit?
bootinfo -y
Q. How
much real memory does my machine have?
bootinfo -r & lsattr -El sys0 -a realmem
Q. How do I get a detailed configuration of my system?
lscfg -vl rmt0
Q. What version, release, and maintenance level of AIX is running on my system?
oslevel -r & lslpp -h bos.rte
Q. How can I determine which fileset updates are missing from a particular AIX level 5300-04?
oslevel -rl 5300-04
Q. What SP (Service Pack) is installed on my system?
oslevel -s
Q. How do I install an individual fix by APAR from cd?
instfix -k IY73748 -d /dev/cd0
Q. How do I verify if filesets have required prerequisites and are completely installed?
lppchk -v
Q. How do I enable or disable SMT?
smtctl [ -m off | on] [ -w boot | now]
Q. How do I get partition-specific information and statistics?
lparstat
Q. How do I know if my volume group is normal, big, or scalable?
Run the lsvg command on the volume group and look at the value for MAX PVs. The value is 32 for normal, 128 for big, and 1024 for scalable volume group.
Q. How do I mirror a logical volume?
1.mklvcopyLogicalVolumeName
Numberofcopies
2.syncvgVolumeGroupName
Q. How do I remove a copy of a logical volume?
rmlvcopy testlv
Q. How
do I find out what the maximum supported logical track group (LTG) size of my
HDD?
#/usr/sbin/lquerypv -M hdisk0
Q. How
can I clone (make a copy of ) the rootvg?
alt_disk_copy -d hdisk1
Q.How can u change IP of one node in
HACMP environment ?
A- SMIT TCP/IP
Q.How to fix if a external storage is
visible to one node and not to other node in HACMP?
A- Using chdev command I will make PVID=yes and command is
chdev -l hdiskn -a PV=yes
Q. How can u increase file system size in HACMP ?
A- Through C-SPOC
Q. How
to Fix if a VG is not Available in ODM?
A- smit importvg
Q.What is heart beat in HACMP ?
A-heartbeat is used for health monitoring of nodes(whether
or not nodes are alive)
Q.
What are the basic requirement for two nodes to be configured in HACMP?
A-each node should have 2 NICs, hardware should be same
and OS and ML must be same
Q. how to check whether a node is in cluster ?
A- using ./clstat
Q. What is the daemon for HACMP?
A- clstrmgrES, clsmuxpdES,clinfoES and clcomdES
Q.
What are the permissions in AIX ?
A- read, write,execute ,SUID,SGID, Sticky bit
Q.How to give all permission, only to
user of a file ?
Q. What is NFS and which daemon it is using, what is
configuration files?
Ans. NFS is network file system which use for sharing file
on the linux/unix plateform.
Server
side daemons are- nfsd, rpc.mountd, rpc.statd, portmap
Client
side daemons are- biod, rpc.statd, portmap
Q. What is portmap?
Ans. It provide port no for client request
Q. How to increase filesystem size?
Ans. Chfs –a +size= m,g /filesystem
Q. What is difference between RAID 0 and RAID 1?
Ans Raid 0 is used for striping purpose and Raid 1 is
using for mirroring.
Q. What is swapon and swapoff command?
Ans Swapon turn on paging space and swapoff used to
turnoff paging space
Q.What is mksysb?
Ans It’s a command which used to take backup of rootvg
Q.What is difference between jfs and
jfs2?
Ansjfs jfs2
1-Inode size 128 Byte 512Byte
2-Max file size 64GB 4PB
3-Max filesystem size 1TB 4PB
4-Compresion yes no
5-jfslog-type General jfslog inline-jfslog
Minimum file system size not specify 16MB
Inode allocation static dynamic
Q. How to start mountd daemon?
Ans startsrc –s mountd
Q. Which is the ODM command to list the ODM object that
stores the PVID?
Ans. odmget -q name=hdisk0 CuAt
Q. What are the basic components of ODM and in which
format data is stored in ODM.
Ans. Components are uniquetype, attribute, deflt and
values. Data is stored in binary format
Q.
Which is the environment variable used by all the ODM commands?And that is set
in file/etc/environment.
What is its default value. [2 marks]
Ans. ODMDIR and default value is /etc/objrepos
Q. Which three types of information are not managed by
ODM? [1/1/2]
Ans. Filesystem information, User/Security information,
Queues and Queue devices.
Q. Which repositories stores the ODM object classes?
[1/1/2]
Ans. /etc/objrepos, /usr/lib/objrepos and
/usr/share/lib/objrepos
Q. Which is the ODM object class used by cfgmgr to
determine the correct sequence when configuring devices. [1/2 mark]
Ans. Config_Rules
Q. What are the contents of Boot Logical Volume? Briefly
explain them? [2 marks]
Ans. AIX Kernel, rc.boot, Reduced ODM and Boot commands.
AIX
kernel– It
is always loaded from the boot logical volume. It provides basic services like
process, memory and device management.
Rc.boot– after starting the kernel, the boot
script rc.boot gets control over the boot process.
Reduced
copy of ODM–
During the boot process many devices are configured before hd4 is available.
For these devices the corresponding ODM files must be stored in the boot
logical volume.
Boot
commands– The
boot commands are programs that are called during the boot process eg.
Bootinfo, cfgmgr.
Q. How to fix a corrupted BLV by using a CD or tape? [2
marks]
Ans. Boot the machine in maintenance mode from a CD or
tape.
Access rootvg.
Run command bosboot –ad /dev/hdiskn
Use savebase command
Use command Shutdown –Fr so that all changes are written
from memory to disk.
Q. List the sequence in which the default boot list in
RS/6000 is stored? [2 marks]
Ans. 1. Diskette Drive
2. CD-ROM
3. Internal disk
4. Communication adapter (like Ethernet or token-ring)
Q. The diag command is part of which package?
Ans. bos.rte.diag [1/2 mark]
Q.How will
you change bootlist for PCI & classical system (MCA) ?
Ans. # bootlist -m normal hdisk1 hdisk0
On some PCI systems (like 43p) bootlist cannot be changed
using the bootlist command. For such systems , we have to change the bootlist
using System Management Services (SMS) menu by pressing F5/F6 key at the time
of system boot.
Q. How do you start & stop a subsystem &
susbsystem group like inetd and tcpip.
Ans. # startsrc -g tcpip --> for starting a group of
services
# startsrc -s inetd --> for starting a single service.
Q. What are the packages to be installed for man pages
& networking?
Ans. bos.info and bos.net
Q. How do you remove an installed package?
Ans. # installp –u –f listfile
Q. What is the use of mkszfile?
Ans. Saves the system state for reinstallation on the current
system or another system. The mkszfile command overwrites an existing
/image.data file with new information.
Q. Write down the command for checking bootlog?
Ans. # alog -o -t boot
Q. How do you change the run level from single user mode
to multiuser mode?
Ans. # telinit 2
Q. Write down the command syntax for listing all supported
and customized devices?
Ans. $ lsdev -C –H --> lists all customized devices
with header
$ lsdev -P –H --> lists all supported devices.
Q.Write the
command for checking the amount of memory for PCI and CLASSICAL RS6000?
Q. Write the command for changing maximum number of user
process from 40 to 80?
Ans. # chdev -l sys0 -a maxuproc=80
Q. How do you configure a defined device?
Ans. # mkdev -l devname
Q. Write down the command for disabling tty0?
Ans. # chdev –l ‘tty0’ –a login=’disable’
Q. Can one printer belongs to multiple queues? If yes then
when do you use this and if no why it's not possible?
Ans. Yes . We use this when the same printer is used under
different emulation like – post script , PCL emulation ,ASCII , etc. We can add
different queues for different emulation.
Q. Can you configure a queue to multiple printers (y/n)?If
yes then write the print command to a queue on a specific printer? If no write
down the reason.
Ans. Yes, $ lpr –P lp0:
Q. What is the command syntax for testing queue status?
Ans. $ lpstat –t
Q. Where does the information about queues and printer
stored?
Ans. /etc/qconfig
Q. Write down the command syntax for changing the
priorities of a print job?
Ans. # qpri - # JobNumber -a PriorityNumber
The job number and priority number can be obtained by
running the lpstat –t command. The priority can only be changed by printer
administrator or system administrator.
Q. Write down commands syntax for listing all VG and
content of a single vg?
Ans. $ lsvg --> lists all volume groups.
$ lsvg –o --> lists only active volume groups.
$ lsvg --> displays characteristics of
volume group.
$ lsvg –l --> logical volumes
$ lsvg –p --> physical volumes
Q.Write
down the command to find out which PV belongs to which VG?
Ans. $ lspv
Q. Write down command for making a volume group ?
Ans. # mkvg -s –y
-B flag may be used for creating big volume group (
maxpvs. 128)
-t is used for specifying the PP size.
Q. What is the command for synchronizing a logical volume
copy (mirror)?
Ans. # syncvg here name could be VG , PV or a
LV name.
Q. Write down the command for turning off a mirroring of a
logical volume ?
Ans. # rmlvcopy
Q. Can you define different Quotas on different
filesystems for a single user?
Ans. Yes.
Q. How
to go to parent directory ?
Ans. $
cd ..
Q. How to execute .profile without logging in again ?
Ans. $ sh .profile
Q. How
to debug shell script ?
Ans. $ sh -x shellfile.
Q. What is first line in shell script
Ans. #!/usr/bin/ksh - path to the shell but no comments. !
is important.
Q. If you are not able to telnet what are the possible
reasons and how to diagnose it ?
Ans. The possible reasons are:
1. Network connection not through.
2. Wrong IP address.
3. Client not in the same network.
4.
Telnet disabled on the server.edit/etc/inetd.conf
5.check /etc/hosts.allow or /etc/hosts.deny in Ur system,
then rename it.
The problem could be diagnosed using 1.) ping 2.) ifconfig
3.) netstat –v 4.) traceroute
Q. What is the entry in resolv.conf for DNS client ?.
Ans. Domain abc.aus.century.com
nameserver
192.9.209.1
nameserver
192.10.25.5
Q. How to extend lv ?
Ans. # extendlv
Q. What is echo $$ ?
Ans. Returns current shell’s PID
Q. How to unmount a filesystem and if it is not able to
unmount what are the steps ?
Ans. # umount
Q. How to take the backup of a dump?
Ans. # snap -a -o
-a Gathers all system configuration information. This
option requires approximately 8MB of temporary disk space.
-o OutputDevice Copies the compressed image onto diskette
or tape.
Q. How to extend the File systems size ?
Ans. # chfs -a size=Newsize filesystem
-a size=NewSize Specifies the size of the Enhanced
Journaled File System in 512-byte blocks. If Value begins with a +, it is
interpreted as a request to increase the file system size by the specified
amount.
Q. How to see the routing table ?
Ans. $ netstat –rn
-n Shows network addresses as numbers & -r Shows the
routing tables
Q. How to see the arp cache ?
Ans. $ arp -a
Q. What are the daemons for NFS Primary server ?
Ans. nfsd, bind,rpc.statd, portmap
Q. What are the daemons for NIS(Network Information
Service) ?
Ans. ypbind, ypserv, yppasswd, portmap
Q. How to access the NFS mounted File System ?
Ans. Just go to the Directory or Access the directory
under the filesystem
Q.What is
automount ? ( explain briefly )
Ans. a) Used for automatic and transparent mounting and
unmounting of NFS File systems.
2.Based on AutoFS facility.
3.Uses automounter map files to find
the mount directories and mount arguments. Map can be text files or NIS maps.
4.automount command
5.automountd daemon
6.Client-side server
Benefits:
1.Reduces system administration of
/etc/filesystems file particularly if NIS maps are used
2.No pre-mounting of directories not
currently needed thus reducing possibility of client hang due to down server
3.Distributes client workload for NFS
read-only file systems
4.Provides method for single-system
image for clients
no { -a | -d Attribute | -o Attribute [ =NewValue ] }
thewall Specifies the maximum amount of memory, in
kilobytes, that is allocated to the memory pool. In AIX 4.2.1 and earlier, the
default value is 1/8 of real memory or 65536 (64 megabytes), whichever is
smaller. In AIX 4.3, the default value is 1/8 of real memory or 131072 (128
megabytes), whichever is smaller. In AIX 4.3.1, the default value is 1/2 of
real memory or 131072 (128 megabytes), whichever is smaller. In AIX 4.3.2 and
later, the default value depends on whether you are running on a CHRP machine or
not. For non-CHRP machines, the default value is 1/2 of real memory or 262144
(256 megabytes), whichever is smaller. For CHRP machines, the default value is
1/2 of real memory or 1048576 (1 gigabyte). thewall is a runtime attribute.
Q. ODM - where it resides, how to modify,list,etc.,
Ans. ODM resides in /etc/objrepos , /usr/lib/objrepos and
/usr/share/lib/objrepos.
To modify ODM use the following sequence :
# odmget -q"uniquetype=tape/scsi/8mm and
attribute=block_size" PdAt > file
edit the corresponding
attribute.à#
vi file
# odmdelete -o PdAt -q"uniquetype=tape/scsi/8mm and
attribute=block_size"
# odmadd file
To list contents of ODM use lsdev command.
Q. File systems - nbpi, etc., read the theory.
Ans. nbpi – number of bytes per inode.
This feature of filesystem is used when fragmentation of
files are set. If a filesystem contains small files , then it is advantageous
to keep the fragment size small , so that space is not wasted. Normally there
is one inode created for every possible file in a filesystem. However in actual
practice the number of inodes required are quite less. Therefore to save on
space allocated for inodes , we specify the nbpi value.
Q. How do I setup anonymous ftp on my AIX system?
It is a shell
script and will set up a anonymous ftp site on your local RS/6000.àAns.
/usr/lpp/tcpip/samples/anon.ftp
Q.How can I
share files/printers with Windows 95?
Ans. The freeware solution is Samba .Commercial solutions
include Fusion95 from Performance Technology
Q. How do I shrink /usr?
Ans. 1) Remove any unneeded files from /usr.
2) Make sure all filesystems in the root volume group are
mounted. If not, they will not be included in the re-installed system.
3)
Type mkszfile. This will create /image.data that contains a list of the active
filesystems in the root volume group that will be included in the installation
procedure.
4)
Edit /image.data. Change the size of /usr to what you want.
IMPORTANT: Make
sure that you Don't enter a value which is less than the size of the FS
required to contain the current data. Doing so will cause the re-installation
procedure to fail.
5)
chdev -l rmt0 -a block=512 -T
6) Unmount all filesystems that are NOT in the root volume
group.
7)
Varyoff all user-defined volume groups, if any # varyoffvg VGname
8)
Export the user-defined volume groups, if any # exportvg VGname
9)
With a tape in the tape drive, type # mksysb /dev/rmt0
This
will do a complete system backup, which will include information (in the
/image.data file) for the installation procedure on how large the filesystems
are to be created.
10)
Install the backup .
11)
When the installation is complete, you may then import any user-defined volume
groups.
#
importvg -y VGname PVname
where
"VGname" is the name of the volume group, and "PVname" is
the name of any one of the physical volumes in the volume group.
12)
Varyon your user-defined volume groups
#
varyonvg VGname
The
reduction of the filesystems is now complete.
Q. What is LVCB ?
Ans. The logical volume control block (lvcb) is the first
512 bytes of a logical volume. This area holds important information such as
the creation date of the logical volume,
information about mirrored copies, and possible mount
points in a journaled filesystem.
Q. What is the limit on Physical Partitions Per Volume Group?
Ans. 1016 Physical Partitions Per Disk in a Volume Group
In most cases, not all the possible 1016 tracking
partitions are used by a disk.
The default size of each Physical Partition during a
"mkvg" command is 4 MB, which implies that individual disks up to 4
GB can be included into a volume group.
If a
disk larger than 4 GB is added to a VG (based on usage of the default 4 MB size
for PP) the disk addition will fail with a warning message that the PP size
needs to be increased.* There are two instances where this limitation will be
enforced. The first case is when the user tries to use "mkvg" to
create a VG where the number of PP 's on one of the disks in the VG would
exceed 1016. In this case, the user must pick from the available PP ranges of:
1, 2, (4), 8, 16, 32, 64, 128, 256, 512 or 1024 MB and use the "-s"
option to "mkvg". The second case is where the disk which violates
the 1016 limitation is attempting to join a pre-existing VG with the
"extendvg" command. The user can either recreate the volume group
with a larger PP size (which will allow the new disk to work with the 1016
limitation) or the user can create a standalone VG (consisting of a larger PP
size) for the new disk.
Q. Why am I having trouble adding another disk to my VG?
Ans. a.) Not enough space left in the volume group
descriptor area.(VGDA)
b.) Volume group can have a maximum of 32 disks in a
volume group. ( 128 for big VG)
Q.How do I
fix Volume Group Locked?
Ans. Use # (putlvodm -K `getlvodm -v ) #chvg
-u
Q. How do I remove a volume group with no disks?
Ans. Without disks VG can't be live.
Q. How do I get rid of a disk that is no longer really in
the volume group?
Ans. # reducevg -d -f
or if the hdname can't be found:
#
reducevg -d -f
Q. What are the theoritical limits within the LVM?
Ans. The system may have 1 to 255 Volumes Groups (VG's).
Each
VG may contain 1 to 32 Physical Volumes (PV's).
Each
PV may contain upto 1016 Physical Partitions (PP's).
Each
PP may have a size (square of 2) from 1 to 256MB (1024MB for AIX 4.3).
The filesystem and file limits are :
File jfs-Filesystem
3.2.5 2 GB 2 GB
4.1.x 2 GB 1 TB
4.2 64GB 1 TB
4.3 64 GB 1 TB
5.x 1 Tb 4 PB
6.x 4 PB 4 PB
Q. How do I control how hostnames are resolved?
Ans. The default order can be overwritten by creating the
configuration file, /etc/netsvc.conf and specifying the desired order. Both the
default and /etc/netsvc.conf can be overwritten with the environment variable,
NSORDER.
Q. dtlogin ignores .profile?
Ans. Edit .dtprofile and remove # from the last line
containing DTSOURCEPROFILE=true.
Q. How do I transfer files between AIX and DOS disks?
Ans. Install the AIX package bos.dosutils which has
commands for transferring files between DOS diskettes and AIX. The commands are
dosread, doswrite, dosdir, dosdel,
and dosformat.
Q. How do I determine the clock frequency of a RS/6000 by
software ?
Ans. There is no way to find out the clock frequency with
a piece of software
VERY IMPORTANT
1. What are your daily activities?
Ans. My daily activities include the following tasks:
1. To backup mksysb.
2. To work on LVM e.g. File system management.
3. To apply patches using instfix and emgr commands.
4. To manage daemons (Whether the daemons are working or
not. If not working then to restart those daemons.). I get to know about these
through Incident Management tickets.
5. Performance Monitoring using common AIX tools like sar,
vmstat and iostat and ps.
6. Looking at errors using errpt command.
7. Creating LPARs, though its not very occasional
activity.
8. Dynamic resource management among LPARs using DLPAR.
9. Client installation using NIM.
2. How AIX is different from other Unix Operating systems
..?
Ans : LV M Concepts ( Policies …where you can optimize the
performance )
ODM
Dynamic Kernel
Auto Configuration of devices (cfgmgr)
Dynamic increasing of file system
JFS & JFS Log..Prevents the file system corruption.
Booting from alternate Disk
Rootvg Cloning
3. How to install oracle on linux? What are the
prerequisites to install oracle ?
Ans : Need to set kernel parameters, install necessary
fixes, create required users and groups, set path and profile, exact
installation procedure comes documented with oracle installation media.
4. How to u find the system is I/O bound
Ans : If the iowait value is more in the iostat output
system can say I/O bound provided the disk balance are good.
5. How u find system is memory bound?
Ans : By observing the pi&po field in vmstat Output
6. How to see user resource limit
Ans : ulimit –a
7. Boot Process of AIX?
Ans : Post
Locate the blv using bootlist
Load the blv and pass control
Configure the device through cfgmgr
Start init and process /etc/inittab
8. How to recreate BLV?
Ans :Got on SMS mode – access rootvg with mounting then
#bosbot –ad /dev/hdisk0 #shutdown –Fr
9.How to change the maintenance mode?
Ans : Init m
10.How to reset lost password of root?
Ans : Go to SMS mode – access rootvg with mounting then
#passwd then #shutdown –Fr
Device
What is the stage of cfgmgr?
Ans : 1.Check predefined database. 2.Load device driver
from odm and made entry on /dev directory
And
3.Put the entry in customized devices database.
Write the command for changing maximum number of user
process from 40 to 80?
Ans. # chdev -l sys0 -a maxuproc=80
How do you configure a defined device?
Ans. # mkdev -l devname
Write down the command for disabling tty0?
Ans. # chdev –l ‘tty0’ –a login=’disable’
How to make available disk to PV.
Ans: #chdev -l hdisk1 - a pv=yes
How to use chdev ..command … to change the block size of
tape
Ans : chdev -l rmt0 block_size=1024
How to see the default attributes of tape or system
Ans : lsattr -E -l rmt0 -D
lsattr
-E -l sys0 -D
How to remove & delete the device(tape) information
from database.
Ans : rmdev -l rmt0 -d
How to make defined device(tape) to available .
Ans : mkdev -l rmt0
How to see the real memory of the system ?
Ans : lsdev -Cc memory or
lsattr -E -l mem0
how to check lun information of SAN environment in AIX
Ans : using lsdev
How to see the firmware
Ans : lsattr –El sys0 –a fwver
Filesystem
Lists out the Advantage of Having LVM .
Optimizing the LV for maximum performance
Increasing the filesystem size dynamically
Mirroring of LVs
Striping of logical volumes
What is the limitation of LVM ?
Maximum VGs per system is 255
Maximum PVs per VG is 32
Maximum LVs per VG is 256
Maximum PPs per PV is 1016 ( AIX 4.3 supports multiple
numbers )
Striped logical volume can not be mirrored
Moving data acrross VG is not possible
Reducing the size of LV is not possible.
What is superblock
The first block on any file system that contain metadata
of its like no:of inode and free inode etc.
How to restricts the VG spaning on numbers of PVs? Is
there any smit is available?
With mkvg command you have to use -d flag to limit the VG
spanning across more disks
There is not smit available.
How to restricts I/O operation on particular PV?
# chpv -v r pvname
What is the Command used to migrate the PV & LV? Is it
possible to migrate the PV between VGs if not possible, how to copy the LVs
from one VG PV to other VG PVs.
#migratepv
It’s not possible
migratelv
-v VGName -y LVName
How will you create filesystem?
A. crfs -v
fstype -g volgroup -m mountpt -p permission -a size
How will you convert normal vg to big vg.
A. chvg -B vgname
Q9.What is the use of synvg and synclvodm
A. syncvg:to update mirrored lv copy in a vg
synclvodm:Synchronizes
or rebuilds the logical volume control block,
the
device configuration database, and the volume group descriptor areas
on the
physical volumes.
Q9.How many lvs will be created at the time of AIX
installation?
A. This is indexnode containing the information about the
file like filename, filesize, fileowner, filegroup, access date& time,
Modification date & time etc.
Q13-How many pvs possible in Big VG & Scalable VG?
A. This is 128 & 1024
Q14-How will you define the VG?
A # mkvg -s pp_size -t t-factor -y vg_name hsidkx
Q15.How will you change the normal VG to Big VG?
A.
#chvg -B vg_name
Q16-What is t-factor?
1.It is the factor used for define the
no.of PP's in a PV within the VG,if we are putting the value of t-factor 2 it
will extend the max no:of PP's per PV and reduced the max no:of PV's within the
VG
Q17- How many max LV possible in a
scalable VG?
1.These are 4096 per VG
Q18.What is the use of lvlstmajor
command?
Ans- To knows the free Major Number.
Q19.How to increase the filesystem size, can we reduce the
fs size?
Ans- #chfs -a size=+value /fsname, fs size can be reduce
in Aix5.3 not in Aix 5.1
Q20.How will you move pp to particular disk?
Migratelp
To move the first logical partitions of logical volumelv00
to hdisk
Migratelp lv00/1 hdisk1
Q21.How to create LV?
Ans. #mklv -t -y
t- for type it may be jfs,pagingspace,journallog,boot
type.
Q22. How to replace the mirror disk from rootvg?
Ans-#unmirrorvg rootvg pvname
#sysdumpdev
-p /dev/sysdumpnull
#reducevg
rootvg pvname
#rmdev
-dl hdiskx
if
mirror disk is bootable put #chpv -c hdiskx
Now
remove faulty disk and put new one then run #cfgmgr
#extendvg
rootvg hdisky
#mirrorvg
-S rootvg hdisky
#bosboot
-ad /dev/hdisky
#bootlist
-m normal hdisky
Q23. What is Quorum?
This is the voting of VGDA,used to recover the data after
a disk crash,if VGDA area is >51% ,then only the quorum will come in
picture. Quorm is provide datat intigrity, data redundancy in mirrorvg.
Q24.How would you increase(Manage) the Filesystem size?
Ans. This depends upon the name of the filesystem. If its
/usr then normally we have to increase the filesystem, because we don't have
chances of compressing the files. In case of other filesystems like /var, we
compress the old log files. Some times we inspect the data which is not
required, we delete that after taking the backups and consulting the
appropriate persons. In case we have to increase the Filesystem size then we
follow the procedure as: To check the no. of free PPs in filesystems using "lsvg
-p" command and the size of the PP in VG. Then we increase the FS size by:
chfs -a size=+NewSize(M\G\or 512 Bytes multiple)
Name_of_FS
If the no. of free PPs is insufficient then we have to add
new harddisk, extend
the VG and then run the chfs command again.
Q25 What is the command for synchronizing a logical volume
copy (mirror)?
Ans. #
syncvg name could be
VG, PV or LV name.
Q26 Write down the command for turning off a mirroring of
a logical volume ?
Q28. How do I get rid of a disk that is no longer really
in the volume group?
Ans. # reducevg -d -f
#
reducevg -d -f
Q.29 Can you define different Quotas on different
filesystems for a single user?
Ans. Yes.
Q.30 What is LVCB ?
Ans. The logical volume control block (lvcb) is the first
512 bytes of a logical volume. This area holds important information such as
the creation date of the logical volume,
information about mirrored copies, and possible mount
points in a journaled filesystem.
Q.31. File systems - nbpi, etc., read the theory.
Ans. nbpi – number of bytes per inode.
This
feature of filesystem is used when fragmentation of files are set. If a
filesystem contains small files , then it is advantageous to keep the fragment
size small , so that space is not wasted. Normally there is one inode created
for every possible file in a filesystem. However in actual practice the number of
inodes required are quite less. Therefore to save on space allocated for inodes
, we specify the nbpi value.
Q.32. Why am I having trouble adding another disk to my
VG?
Ans. a.) Not enough space left in the volume group
descriptor area.(VGDA)
b.)
Volume group can have a maximum of 32 disks in a volume group. ( 128 for big
VG)
Q33.Difference between fsck –y and fsck –f
Ans : fsck –f: perform the fast check. It will not check
that filesystem were umounted successfully.
FSCK –y : assumes a yes response to all questions asked by
the fsck command
What are the 6 steps in fsck –y
1.Check Block and size
2.Check pathname
3.Check connectivity
4.Check reference counts
5.Check inode map
6.Check block map
Q34.How to create file system in raw
hard disk?
Extendvg, mklv, crfs
Q35.What are the stanza in /etc/filesystem?
Dev= ,Mount= ,Log= ,Vfs= , Check= ,Type=
Q36.What is proc file system?
Contain info about all currently running process
calculation of pp
pv size = 80GB (81920 MB)
default no of pp = 1016
pp size = h/d in mb / default no of pp (81920/1016) = 80mb
(>64) that’s why 128 mb
if we want to increase no of pp = t factor increase
no of pp = default no of pp * t factor ( 1016*2 = 2032 pp)
according that if we want to decrease size of PP then we
have to increase t factor mean no of pp
ppsize now = 81920/2032 = 40mb means >32 that’s why
it’s a 64 mb
Q37.How you will maintain the password polices?
Using chuser and /etc/security/user
Q38.What is journaled file system?
It maintains a log in corresponding log device before
committing any changes to LV and thus maintains integrity of file system.
Boot & dump * Error & ODM
Q.1. How to see memory activity ?
Ans. Using "sar", "vmstat"
Q2.What is difference between tar and cpio?
Ans : Tar handle symbolic link. cpio doesn’t.
Q3.What will do when odm in non-rootvg corrupted? (Rename
vg also)
Ans :Exportvg and importvg
Q4.Why quorum is disabled in mirroring.
Ans : If it is mirrored within two pv VGDA will be three,
one will have two VGDA means 66%, another ill have one VGDA means 33% , we
can`t activate which failed with in 51% VGDA.. that’s what quorum is disabled
in two mirrored condition.
Q5.Will file system extend or reduce update the vgda?
Ans : Yes as the use of pp is maintained by the vgda
Q.6. How
to install software ?
Ans. # installp –a –Q –d -f ‘all latest’
-a
Applies one or more software products or updates.
-d Device Specifies where the installation media can be
found.
-f
ListFile Reads the names of the software products from ListFile.
Q.7 What are the packages to be installed for man pages
& networking?
Ans. bos.info and bos.net
Q.8 How do you remove an installed package?
Ans. # installp –u –f listfile
Q.9 What is the use of mkszfile?
Ans. Saves the system state for reinstallation on the
current system or another system. The mkszfile command overwrites an existing
/image.data file with new information.
Q.10 Write down the command for checking bootlog?
Ans. # alog -o -t boot
Q.11. How
to take the backup of a dump?
Ans. # snap -a -o
Q.12 What is echo $$ ?
Ans. Returns current shell’s PID
Q.13. How to debug shell script ?
Ans. $ sh -x shellfile.
Q.14 What are the packages to be installed for man pages
& networking?
Ans. bos.info and bos.net
Q.15 How do you remove an installed package?
Ans. # installp –u –f listfile
Q16.How will you delete an entry from ODM?
Ans : #odmdelete
Q17.What is the component of BLV?
Ans- These are Reduce ODM, RAMfs, Aix Kernel, Aix Commands
Q18.How to Recover BLV if corrupted, which LED will Glow
for that?
Ans-Boot the system by Cd or tape in Maintenance mode and
access the rootvg then run #bosboot -ad /dev/hdiskx command set set the
bootlist and restart the system. LED 557 will glow.
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