1. To confirm which network adapter is plugged into the switch in IBM AIX
Try this next time to confirm what adapter is actually plugged in to a switch:
This will not only tell you where you have a connection but it will also tell you what speed the port on the switch is.
# netstat -v |grep -E "ETHERMedia"
ETHERNET STATISTICS (ent0) :
Media Speed Selected: 100 Mbps Full Duplex
Media Speed Running: 100 Mbps Full Duplex
ETHERNET STATISTICS (ent1) :
Media Speed Selected: 1000 Mbps Full Duplex
Media Speed Running: 1000 Mbps Full Duplex
----------------------------------------------------------------------------------------------------------------
2. How to determine if IBM AIX 64 bit kernel (sotware) is installed on your IBM AIX server?
# lslpp -l bos.64bit
bos.64bit 4.3.3.76 COMMITTED Base Operating System 64 bit
----------------------------------------------------------------------------------------------------------------
3. How you create a snapshot of your IBM AIX server to send to IBM for tech support ?
This is requried whenver you face issues with your server and you seek help from IBM to sort out the issue.
# snap -gc
This will create a file called snap.pax.Z in the directory /tmp/ibmsupt. Send this file to IBM so that they will get full configuration of your server.
----------------------------------------------------------------------------------------------------------------
4. How to enable entended history in AIX 5.3 ?
In AIX 5.3, you have the capability to have a time stamped history. To enable it, just set the following variable:
EXTENDED_HISTORY=ON
Example:
export EXTENDED_HISTORY=ON
If required add this line to your .profile.
----------------------------------------------------------------------------------------------------------------
5. How to find the microcode level of tape drives ?
To find microcode level (firmware) of tape drives in IBM AIX:
# tapeutil -f /dev/rmt1 vpd
----------------------------------------------------------------------------------------------------------------
6. pgrep and pkill - how to terminate processes ?
You can use the pgrep and pkill commands to identify and stop command processes that you no longer want to run. These commands are useful when you mistakenly start a process that takes a long time to run.
To terminate a process:
a. pgrep - to find out the PID(s) for the process(es)
b. pkill - followed by the PID(s)
The following example illustrates how to find all the processes with a specific name (xterm) and terminate the xterm process that was started last.
# pgrep xterm 17818 17828 17758 18210
# pkill -n 18210
Note: If you need to forcibly terminate a process, use the -9 option to the pkill command.
For Example
# kill -9 -n xterm
----------------------------------------------------------------------------------------------------------------
7. How to modify Asynchronous I/O variables in AIX ?
To modify the minservers asynchronous I/O variable (MINIMUM number of servers) in IBM AIX:
# chdev -l aio0 -a minservers='1'
To modify the maxservers asynchronous I/O variable (MAXIMUM number of servers per cpu) in IBM AIX 5L:
# chdev -l aio0 -a maxservers='10'
To modify the maxservers asynchronous I/O variable (MAXIMUM number of servers) in IBM AIX v4.3:
# chdev -l aio0 -a maxservers='80'
To modify the requests asynchronous I/O variable (Maximum number of REQUESTS) in IBM AIX:
# chdev -l aio0 -a requests='4096'
Notes:
1) Valeus will only take effect after a reboot
2) You may use multiple -a options on the same command line3)
The maxservers variable is PER CPU for AIX 5L and TOTAL for AIX v4.3
----------------------------------------------------------------------------------------------------------------
8. How to display microcode and firmware levels of the system and adapters in IBM AIX ?
To displays microcode level information for all supported devices in IBM AIX :
# lsmcode -A
sys0!system:SF240_284 (t) SF240_261 (p) SF240_284 (t)
ent0!14108902.DV0210
ent1!14108902.DV0210
ent2!14108902.DV0210
ent3!14108902.DV0210
sisscsia0!44415254.05080064
sisscsia1!44415255.050A0064
hdisk0!ST37320.4A553042.43373038
hdisk1!ST37320.4A553042.43373038
----------------------------------------------------------------------------------------------------------------
9. How to determine if simultaneous multi-threading (SMT) is enabled in AIX ?
Your system is capable of SMT if it's a POWER5-based system running AIX 5L Version 5.3.To determine if it is enabled:# smtctl
To enable SMT: # smtctl -m on [ -w boot now]
To disable SMT: # smtctl -m off [ -w boot now]
Note: If neither the -w boot or the -w now options are specified, then the mode change is made immediately. It persists across subsequent reboots if you run the bosboot command before the next system reboot.
----------------------------------------------------------------------------------------------------------------
10. How to find top users of memory space in IBM AIX ?
To list the top ten users of paging space in IBM AIX:
# svmon -Pgt 10
To list the top ten users of realmem in IBM AIX:
# svmon -Put 10
----------------------------------------------------------------------------------------------------------------
11. How to list the filesystems in a volume group in IBM AIX ?
# lsvgfs volume_group
----------------------------------------------------------------------------------------------------------------
12. How to query the volume group descriptor area on a drive in IBM AIX ?
To query the volume group descriptor area on the drive, so you can find out if there's a VG on the disk, even if there isn't anything imported on the drive in IBM AIX:
# lqueryvg -Atp hdisk#
----------------------------------------------------------------------------------------------------------------
13. How to set IBM AIX for full core dumps and files to unlimited
To set IBM AIX for full core dumps to unlimited:
# ulimit -c unlimited
To set IBM AIX for files to unlimited:
# ulimit -f unlimited
To view your ulimit settings:
# ulimit –a
----------------------------------------------------------------------------------------------------------------
14. How to determine what the speed and duplex is of an interface in AIX ?
# entstat -d en0 grep "Media Speed"
------------------------------------------------------------------------------------------------
15. How to find the highest technology level and service pack installed in IBM AIX ?
Starting in 2006, in IBM AIX, a Maintenance Level will be referred to as a Technology Level and will only be released twice per year.
The Service Pack concept will allow service-only updates (as known as PTF’s) that are released between Technology Levels to be grouped together for easier identification.
Sample output for a V5.3 system, with Technology Level 4, and Service Pack 2 installed would be:
# oslevel –s
----------------------------------------------------------------------------------------------------------------
16. How to find number of active processors in IBM AIX ?
To find the number of active processors in IBM AIX:
# bindprocessor -q
The available processors are: 0 1 2
To find the number of processors installed (but not necessarily available):
# lscfg -v grep proc
proc0 00-00 Processor
proc2 00-02 Processor
proc4 00-04 Processor
----------------------------------------------------------------------------------------------------------------
17. How to read the contents of /etc/security/failedlogin in IBM AIX ?
# who /etc/security/failedlogin# /usr/sbin/acct/fwtmp < /etc/security/failedlogin
----------------------------------------------------------------------------------------------------------------
18. How to reserve or lock a terminal under AIX 5L ?
This command will lock your terminal and reserve it for later use in AIX 5L
# lock
# lock -30 (lock for 30 minutes)
Note: default lock time is 15 mintes lock will ask you for a password twice then lock the terminal. you can unlock it by entering the password a third time.
----------------------------------------------------------------------------------------------------------------
19. How to stop IBM AIX from forcing a user to change their password at first login ?
# pwdadm -c username
----------------------------------------------------------------------------------------------------------------
20. Redhat Package Manager for IBM AIX and Linux
To query all packages installed:
# rpm -q –a
To list file in a specific package:
# rpm -q -l package.rpm
To install a RPM package:
# rpm -i package.rpm
To delete (erase) a RPM package:
# rpm -e package.rpm
To query for RPM package owning file:
# rpm -q -f /path/to/file
To upgrade a RPM package
# rpm -U package.rpm
----------------------------------------------------------------------------------------------------------------
21. How to capture TCPIP packet information in IBM AIX ?
Here is a command to capture TCP/IP packet information between your server and another in IBM AIX:
Become root user, Find a temporary directory to capture the data (/tmp in this example) Run the iptrace command:
# iptrace -a -d host_destination -b /tmp/ip.out
iptrace will run in the background and results will be in /tmp/ip.out
To see the results of the trace:
# ipreport /tmp/ip.out more
Don't foregt to kill iptrace when you're done:
# ps -ef grep iptrace grep -v grep awk '{system("kill " $2)}'
Some other cool options of iptrace:
-d : specify destination IP address -s : specify origin IP address
-b : show 2-way traffic (as in "-s xxx -b" or "-d xxx -b")
-a : no ARP requests (less pollution in the trace)
To see all packets going in and out of server, unixserv, without ARP requests:
# iptrace -a -d unixserv -b /tmp/ip.out
iptrace and ipreport are in IBM AIX LPP "bos.net.tcp.server"
----------------------------------------------------------------------------------------------------------------
22. How to check if a system dump completed successfully on IBM AIX ?
To verify if a system dump completed successfully on an IBM AIX server:
# sysdumpdev –L
0453-039
Device name: /dev/hd6
Major device number: 10
Minor device number: 1
Size: 124371456 bytes
Date/Time: Sun Sep 15 12:19:02 EDT 2002
Dump status: 0 ( 0 = Ok)
dump completed successfully
0481-195
Failed to copy the dump from /dev/hd6 to /var/adm/ras
----------------------------------------------------------------------------------------------------------------
23. How to check two file systems simultaneously on different drives in IBM AIX ?
To check two file systems simultaneously on different drives in IBM AIX.The dfsck command permits you to interact with two fsck commands at once. To aid in this, the dfsck command displays the file system name with each message. When responding to a question from the dfsck command, prefix your response with a 1 or a 2 to indicate whether the answer refers to the first or second file system group.
# dfsck [ FlagList1 ] FileSystem1 [ FlagList2 ] FileSystem2
Example to check two filesystems:
# dfsck -p /dev/hd1 - -p /dev/hd7
Note: you can also specify the file system names found in the /etc/filesystems. Attention: Do not use the dfsck command to check the root file system.
----------------------------------------------------------------------------------------------------------------
24. How to make a disk flash in IBM AIX ?
For disk replacement, it is often useful to make the disk flash so that you know which disk to replace in IBM AIX:
# diag to continue
Select "Task Selection (Diagnostics, Advanced Diagnostics, Service Aids, etc.)"
Select "Hot Plug Task"Select "SCSI and SCSI RAID Hot Plug Manager"
Select "Identify a Device Attached to a SCSI Hot Swap Enclosure Device"
Select the slot you wish the disk to flash Replace the appropriate disk by checking which disk is flashing
----------------------------------------------------------------------------------------------------------------
25. How to determine which application created the OS core file in AIX ?
# /usr/sbin/lquerypv -h /path/to/core 6b0 64
The output of this command is neat, clean and easy to read.
Here is an example:
# lquerypv -h core 6b0 64
000006B0 7FFFFFFF FFFFFFFF 7FFFFFFF FFFFFFFF ................
000006C0 00000000 000007D0 7FFFFFFF FFFFFFFF ................
000006D0 00120000 1312C9C0 00000000 00000017 ................
000006E0 6E657473 63617065 5F616978 34000000 netscape_aix4...
000006F0 00000000 00000000 00000000 00000000 ................
00000700 00000000 00000000 00000000 00000ADB ................
00000710 00000000 000008BF 00000000 00000A1E ................
The executable is located between the pipes on the right hand side of the output. In this case, the core was generated by Netscape.
----------------------------------------------------------------------------------------------------------------
26. How to find the system id number of an IBM AIX server ?
# lsattr -El sys0 -a systemid
# uname -u
# lscfg -vpgrep -p "System VPD:" grep -i Serial
Note: commands may not work on all IBM models
----------------------------------------------------------------------------------------------------------------
27. Tips on Memory Tuning :
Do not use the command vmtune in AIX 5L. From AIX 5L. vmo and ioo commands are introduced to tune memory and I/O.
Here is how we set various memory options now:
# vmo -p -o maxfree=128
# vmo -p -o minperm%=5
# vmo -p -o maxclient%=10
# vmo -p -o maxperm%=10
# vmo -p -o maxfree=632
# vmo -p -o minfree=600
# ioo -p -o maxpgahead=32
To see the results of the changes:
# vmo –L
# ioo –L
If you have a problem with slow telnet sessions:
# chdev -l sys0 -a maxpout='33' -a minpout='24'
To set AIO (asynchronous IO) options use smitty
----------------------------------------------------------------------------------------------------------------
28. If you reinstall an IBM AIX server and the mksysb used was for a server on another vlan, you can end up with 2 default routes. Lets see how to solve this issue
In order to see the default routes stored in the ODM:
# lsattr -El inet0 grep Route
route net,-hopcount,0,,0,172.26.247.92 Route True
route net,-hopcount,0,,0,172.26.14.1 Route True
To see the default routes you have in your routing table:
# netstat -rn grep default
default 172.26.14.1 UGc 0 0 en0 - - =>
default 172.26.247.92 UGc 0 0 en0 - -
To remove one of the default routes, use smitty and not a the route command otherwise you will end up with 2 default routes after a reboot.
----------------------------------------------------------------------------------------------------------------
29. EFix - How to manage ?
To list efix :
# emgr –l
To install an efix package:
# emgr -e efixPackage
----------------------------------------------------------------------------------------------------------------
30. Kernel Processes in AIX: An Overview
# ps -kl
# pstat -a (as root)
There are several kprocs, and they do a number of things. Often they have fixed priority and will run ahead of any user processes.
A couple are:
Kproc Kernel (wait) wait process
Kproc Kernel (lrud) Least Recently Used Daemon (mem mgmt)
Kproc Kernal (swapper) Memory/Process swapping ?
Kproc Kernel (kbiod) Kernel Block I/O daemon (disk I/O)?
kproc Kernel ( gil) 1032 Networking off-level stuff
Kproc Kernel (netm) Network memory allocator
Kproc Kernel (aump) Automounter
A kproc is a kernel process, started by the kernel on behalf of either another kernel process, or as a result of an application initiating a system call or call to a kernel service.
Wait - You will find that the "wait" kproc will have accumulated a lot of cpu time. This just means your system is idle a lot. When nothing else needs to run, the wait kproc is charged the time slice
GIL - "Global ISR List"
ISR->Interrupt Service Routines - multithreaded kproc runs at fixed pri of 37 Used to process various timers (tcp, streams, ....) and also used to pass packets from demux layer to IP layer for non-CDLI drivers.
ps -lk
The processes with nice value of -- are running with fixed priorities. Their nice values can not be changed. On my system that would processes such as swapper (pid=0, pri=16) and the wait kproc (pid=514, pri=127).
This will list out all the kprocs. Now do a pstat -a to find what they really are?
This will show you the real name of the kproc.
Aump kernel thread is left over after you stop the automounter daemon.
Yes. It goes away after reboot. However, there is an APAR for it: IY33240
----------------------------------------------------------------------------------------------------------------
31. How to manage network tuning parameters in AIX ?
The no command is used to configure network tuning parameters in IBM AIX. The no command sets or displays current or next boot values for network tuning parameters. This command can also make permanent changes or defer changes until the next reboot.
Syntax:
no [ -p -r ] { -o Tunable[=NewValue] }
no [ -p -r ] {-d Tunable }
no [ -p -r ] { -D }
no [ -p -r ] -a
no -h [ Tunable ]
no -L [ Tunable ]
no -x [ Tunable ]
where:
-a : displays current, reboot or permanent value for all tunable parameters
-d : resets Tunable its to default value
-D : resets all tunables to their default value
-h : displays help about Tunable parameter
-L : lists the characteristics of one or all Tunables
-o : displays the value or sets the Tunable to NewValue
-p : makes changes apply to both current and reboot values (I heard this option in many interviews)
-r : makes changes apply to reboot values (I heard this option in many interviews)
-x : lists characteristics of one or all tunables using spreadhset format
Example to set the value of tunable tcp_sendspace to 65536 permanently:
# no -p -o tcp_sendspace=65536
Example to set the value of tunable sb_max to 2097152 at next reboot:
# no -r -o sb_max=2097152
Example to display all values of tunables:
# no -a
Example to display all values of tunables at next reboot:
# no -r -a
Example to set the value of tunable tcp_sendspace to 65536:
# no -o tcp_sendspace=65536
----------------------------------------------------------------------------------------------------------------
32. How to verify your ntp setup is working properly ?
# ntpq -c peersremote refid st t when poll reach delay offset disp =========================================================================
*time.domain.co doghaus.cns.uto 3 u 12 64 177 1.46 -2.515 145.19
If you have a star (*) in the first column of the name of the time server, your time is being synchronised properly.
The third column, st, is the stratum. The lower the number, the closer you are to the time source.
Stratum 16 means you are not synchronised.
----------------------------------------------------------------------------------------------------------------
33. How to synchronize your server time to a time server ?
If you don't want to run NTP (network time protocol), you can update your system time with the command:
# ntpdate timeserver.domain.com
----------------------------------------------------------------------------------------------------------------
34.How to list open files ?
To list all open files:
# lsof
To list all open files on a device:
# lsof /dev/hd4
----------------------------------------------------------------------------------------------------------------
35. How to find the world-wide name (WWN) or network address of a fibre-channel (FC) card in IBM AIX ?
First find the name of your fibre-channel cards:
# lsdev -vp grep fcs
Then get the WWN (for fcs0 in this example):
# lscfg -vp -l fcs0 grep "Network Address"
----------------------------------------------------------------------------------------------------------------
36. How to change a server hostname with the uname command in IBM AIX ?
To display the current hostname
# uname -n
localhost
To change the hostname
# uname -S newhostname
Again display the hostname
# uname -n
newhostname
----------------------------------------------------------------------------------------------------------------
37. How can you find out when a system was installed?
Enter the following command:
lslpp -h bos.rte
The output of this command will show the history of when the operating system was installed. Read the entry for the AIX level (ie, 4.3.3.0).
----------------------------------------------------------------------------------------------------------------
38. How to make sure all of the user definitions are correct in the user database
#usrck -n ALL
Do the same for the groups:
#grpck -n ALL
----------------------------------------------------------------------------------------------------------------
39. Reduce the Size of a File System in Your Root Volume Group ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_baseadmn_rootvg_reduce.htm#baseadmn_rootvg_reduce
----------------------------------------------------------------------------------------------------------------
40.How to reset an Unknown Root Password ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_baseadmn_recoverrootpswd.htm#baseadmn_recoverrootpswd
----------------------------------------------------------------------------------------------------------------
41. How to configure Domain Name Servers ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_commadmn_dns.htm#commadmn_dns
-----------------------------------------------------------------------------------------------------------------
42. How to re-create corrupted boot image ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_baseadmn_bad_boot_img.htm#baseadmn_bad_boot_img
----------------------------------------------------------------------------------------------------------------
43. How to configure NIM master server using EZNIM ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_insgdrf_configure_eznim.htm#insgdrf_configure_eznim
----------------------------------------------------------------------------------------------------------------
44. How do I use network (For normal users)
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/Use_Network_U.htm#category_use_network
----------------------------------------------------------------------------------------------------------------
45. How do I view system and environment information?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/AccessSys_Envir_U.htm#category_accesssys_envir
----------------------------------------------------------------------------------------------------------------
46. How do I use shell scripts ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/Use_Shells_U.htm#category_use_shells
----------------------------------------------------------------------------------------------------------------
47. How do I redirect standard input, output, and error?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/RedirStand_IO_Error_U.htm#category_redirstand_io_error
------------------------------------------------------------------------------------------------
48. How do I make my system more secure?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/Security_U.htm#category_security
49. How to configure network adapters for Redundancy ?
http://users.ca.astound.net/~baspence/AIXtip/etherchannel.htm
----------------------------------------------------------------------------------------------------------------
50. Useful link about AIX Error Log codes, LED codes, 7-Digit Error codes.
http://rainsux.dyndns.org/AIX5L-Messages-Codes.html
Try this next time to confirm what adapter is actually plugged in to a switch:
This will not only tell you where you have a connection but it will also tell you what speed the port on the switch is.
# netstat -v |grep -E "ETHERMedia"
ETHERNET STATISTICS (ent0) :
Media Speed Selected: 100 Mbps Full Duplex
Media Speed Running: 100 Mbps Full Duplex
ETHERNET STATISTICS (ent1) :
Media Speed Selected: 1000 Mbps Full Duplex
Media Speed Running: 1000 Mbps Full Duplex
----------------------------------------------------------------------------------------------------------------
2. How to determine if IBM AIX 64 bit kernel (sotware) is installed on your IBM AIX server?
# lslpp -l bos.64bit
bos.64bit 4.3.3.76 COMMITTED Base Operating System 64 bit
----------------------------------------------------------------------------------------------------------------
3. How you create a snapshot of your IBM AIX server to send to IBM for tech support ?
This is requried whenver you face issues with your server and you seek help from IBM to sort out the issue.
# snap -gc
This will create a file called snap.pax.Z in the directory /tmp/ibmsupt. Send this file to IBM so that they will get full configuration of your server.
----------------------------------------------------------------------------------------------------------------
4. How to enable entended history in AIX 5.3 ?
In AIX 5.3, you have the capability to have a time stamped history. To enable it, just set the following variable:
EXTENDED_HISTORY=ON
Example:
export EXTENDED_HISTORY=ON
If required add this line to your .profile.
----------------------------------------------------------------------------------------------------------------
5. How to find the microcode level of tape drives ?
To find microcode level (firmware) of tape drives in IBM AIX:
# tapeutil -f /dev/rmt1 vpd
----------------------------------------------------------------------------------------------------------------
6. pgrep and pkill - how to terminate processes ?
You can use the pgrep and pkill commands to identify and stop command processes that you no longer want to run. These commands are useful when you mistakenly start a process that takes a long time to run.
To terminate a process:
a. pgrep - to find out the PID(s) for the process(es)
b. pkill - followed by the PID(s)
The following example illustrates how to find all the processes with a specific name (xterm) and terminate the xterm process that was started last.
# pgrep xterm 17818 17828 17758 18210
# pkill -n 18210
Note: If you need to forcibly terminate a process, use the -9 option to the pkill command.
For Example
# kill -9 -n xterm
----------------------------------------------------------------------------------------------------------------
7. How to modify Asynchronous I/O variables in AIX ?
To modify the minservers asynchronous I/O variable (MINIMUM number of servers) in IBM AIX:
# chdev -l aio0 -a minservers='1'
To modify the maxservers asynchronous I/O variable (MAXIMUM number of servers per cpu) in IBM AIX 5L:
# chdev -l aio0 -a maxservers='10'
To modify the maxservers asynchronous I/O variable (MAXIMUM number of servers) in IBM AIX v4.3:
# chdev -l aio0 -a maxservers='80'
To modify the requests asynchronous I/O variable (Maximum number of REQUESTS) in IBM AIX:
# chdev -l aio0 -a requests='4096'
Notes:
1) Valeus will only take effect after a reboot
2) You may use multiple -a options on the same command line3)
The maxservers variable is PER CPU for AIX 5L and TOTAL for AIX v4.3
----------------------------------------------------------------------------------------------------------------
8. How to display microcode and firmware levels of the system and adapters in IBM AIX ?
To displays microcode level information for all supported devices in IBM AIX :
# lsmcode -A
sys0!system:SF240_284 (t) SF240_261 (p) SF240_284 (t)
ent0!14108902.DV0210
ent1!14108902.DV0210
ent2!14108902.DV0210
ent3!14108902.DV0210
sisscsia0!44415254.05080064
sisscsia1!44415255.050A0064
hdisk0!ST37320.4A553042.43373038
hdisk1!ST37320.4A553042.43373038
----------------------------------------------------------------------------------------------------------------
9. How to determine if simultaneous multi-threading (SMT) is enabled in AIX ?
Your system is capable of SMT if it's a POWER5-based system running AIX 5L Version 5.3.To determine if it is enabled:# smtctl
To enable SMT: # smtctl -m on [ -w boot now]
To disable SMT: # smtctl -m off [ -w boot now]
Note: If neither the -w boot or the -w now options are specified, then the mode change is made immediately. It persists across subsequent reboots if you run the bosboot command before the next system reboot.
----------------------------------------------------------------------------------------------------------------
10. How to find top users of memory space in IBM AIX ?
To list the top ten users of paging space in IBM AIX:
# svmon -Pgt 10
To list the top ten users of realmem in IBM AIX:
# svmon -Put 10
----------------------------------------------------------------------------------------------------------------
11. How to list the filesystems in a volume group in IBM AIX ?
# lsvgfs volume_group
----------------------------------------------------------------------------------------------------------------
12. How to query the volume group descriptor area on a drive in IBM AIX ?
To query the volume group descriptor area on the drive, so you can find out if there's a VG on the disk, even if there isn't anything imported on the drive in IBM AIX:
# lqueryvg -Atp hdisk#
----------------------------------------------------------------------------------------------------------------
13. How to set IBM AIX for full core dumps and files to unlimited
To set IBM AIX for full core dumps to unlimited:
# ulimit -c unlimited
To set IBM AIX for files to unlimited:
# ulimit -f unlimited
To view your ulimit settings:
# ulimit –a
----------------------------------------------------------------------------------------------------------------
14. How to determine what the speed and duplex is of an interface in AIX ?
# entstat -d en0 grep "Media Speed"
------------------------------------------------------------------------------------------------
15. How to find the highest technology level and service pack installed in IBM AIX ?
Starting in 2006, in IBM AIX, a Maintenance Level will be referred to as a Technology Level and will only be released twice per year.
The Service Pack concept will allow service-only updates (as known as PTF’s) that are released between Technology Levels to be grouped together for easier identification.
Sample output for a V5.3 system, with Technology Level 4, and Service Pack 2 installed would be:
# oslevel –s
----------------------------------------------------------------------------------------------------------------
16. How to find number of active processors in IBM AIX ?
To find the number of active processors in IBM AIX:
# bindprocessor -q
The available processors are: 0 1 2
To find the number of processors installed (but not necessarily available):
# lscfg -v grep proc
proc0 00-00 Processor
proc2 00-02 Processor
proc4 00-04 Processor
----------------------------------------------------------------------------------------------------------------
17. How to read the contents of /etc/security/failedlogin in IBM AIX ?
# who /etc/security/failedlogin# /usr/sbin/acct/fwtmp < /etc/security/failedlogin
----------------------------------------------------------------------------------------------------------------
18. How to reserve or lock a terminal under AIX 5L ?
This command will lock your terminal and reserve it for later use in AIX 5L
# lock
# lock -30 (lock for 30 minutes)
Note: default lock time is 15 mintes lock will ask you for a password twice then lock the terminal. you can unlock it by entering the password a third time.
----------------------------------------------------------------------------------------------------------------
19. How to stop IBM AIX from forcing a user to change their password at first login ?
# pwdadm -c username
----------------------------------------------------------------------------------------------------------------
20. Redhat Package Manager for IBM AIX and Linux
To query all packages installed:
# rpm -q –a
To list file in a specific package:
# rpm -q -l package.rpm
To install a RPM package:
# rpm -i package.rpm
To delete (erase) a RPM package:
# rpm -e package.rpm
To query for RPM package owning file:
# rpm -q -f /path/to/file
To upgrade a RPM package
# rpm -U package.rpm
----------------------------------------------------------------------------------------------------------------
21. How to capture TCPIP packet information in IBM AIX ?
Here is a command to capture TCP/IP packet information between your server and another in IBM AIX:
Become root user, Find a temporary directory to capture the data (/tmp in this example) Run the iptrace command:
# iptrace -a -d host_destination -b /tmp/ip.out
iptrace will run in the background and results will be in /tmp/ip.out
To see the results of the trace:
# ipreport /tmp/ip.out more
Don't foregt to kill iptrace when you're done:
# ps -ef grep iptrace grep -v grep awk '{system("kill " $2)}'
Some other cool options of iptrace:
-d : specify destination IP address -s : specify origin IP address
-b : show 2-way traffic (as in "-s xxx -b" or "-d xxx -b")
-a : no ARP requests (less pollution in the trace)
To see all packets going in and out of server, unixserv, without ARP requests:
# iptrace -a -d unixserv -b /tmp/ip.out
iptrace and ipreport are in IBM AIX LPP "bos.net.tcp.server"
----------------------------------------------------------------------------------------------------------------
22. How to check if a system dump completed successfully on IBM AIX ?
To verify if a system dump completed successfully on an IBM AIX server:
# sysdumpdev –L
0453-039
Device name: /dev/hd6
Major device number: 10
Minor device number: 1
Size: 124371456 bytes
Date/Time: Sun Sep 15 12:19:02 EDT 2002
Dump status: 0 ( 0 = Ok)
dump completed successfully
0481-195
Failed to copy the dump from /dev/hd6 to /var/adm/ras
----------------------------------------------------------------------------------------------------------------
23. How to check two file systems simultaneously on different drives in IBM AIX ?
To check two file systems simultaneously on different drives in IBM AIX.The dfsck command permits you to interact with two fsck commands at once. To aid in this, the dfsck command displays the file system name with each message. When responding to a question from the dfsck command, prefix your response with a 1 or a 2 to indicate whether the answer refers to the first or second file system group.
# dfsck [ FlagList1 ] FileSystem1 [ FlagList2 ] FileSystem2
Example to check two filesystems:
# dfsck -p /dev/hd1 - -p /dev/hd7
Note: you can also specify the file system names found in the /etc/filesystems. Attention: Do not use the dfsck command to check the root file system.
----------------------------------------------------------------------------------------------------------------
24. How to make a disk flash in IBM AIX ?
For disk replacement, it is often useful to make the disk flash so that you know which disk to replace in IBM AIX:
# diag to continue
Select "Task Selection (Diagnostics, Advanced Diagnostics, Service Aids, etc.)"
Select "Hot Plug Task"Select "SCSI and SCSI RAID Hot Plug Manager"
Select "Identify a Device Attached to a SCSI Hot Swap Enclosure Device"
Select the slot you wish the disk to flash Replace the appropriate disk by checking which disk is flashing
----------------------------------------------------------------------------------------------------------------
25. How to determine which application created the OS core file in AIX ?
# /usr/sbin/lquerypv -h /path/to/core 6b0 64
The output of this command is neat, clean and easy to read.
Here is an example:
# lquerypv -h core 6b0 64
000006B0 7FFFFFFF FFFFFFFF 7FFFFFFF FFFFFFFF ................
000006C0 00000000 000007D0 7FFFFFFF FFFFFFFF ................
000006D0 00120000 1312C9C0 00000000 00000017 ................
000006E0 6E657473 63617065 5F616978 34000000 netscape_aix4...
000006F0 00000000 00000000 00000000 00000000 ................
00000700 00000000 00000000 00000000 00000ADB ................
00000710 00000000 000008BF 00000000 00000A1E ................
The executable is located between the pipes on the right hand side of the output. In this case, the core was generated by Netscape.
----------------------------------------------------------------------------------------------------------------
26. How to find the system id number of an IBM AIX server ?
# lsattr -El sys0 -a systemid
# uname -u
# lscfg -vpgrep -p "System VPD:" grep -i Serial
Note: commands may not work on all IBM models
----------------------------------------------------------------------------------------------------------------
27. Tips on Memory Tuning :
Do not use the command vmtune in AIX 5L. From AIX 5L. vmo and ioo commands are introduced to tune memory and I/O.
Here is how we set various memory options now:
# vmo -p -o maxfree=128
# vmo -p -o minperm%=5
# vmo -p -o maxclient%=10
# vmo -p -o maxperm%=10
# vmo -p -o maxfree=632
# vmo -p -o minfree=600
# ioo -p -o maxpgahead=32
To see the results of the changes:
# vmo –L
# ioo –L
If you have a problem with slow telnet sessions:
# chdev -l sys0 -a maxpout='33' -a minpout='24'
To set AIO (asynchronous IO) options use smitty
----------------------------------------------------------------------------------------------------------------
28. If you reinstall an IBM AIX server and the mksysb used was for a server on another vlan, you can end up with 2 default routes. Lets see how to solve this issue
In order to see the default routes stored in the ODM:
# lsattr -El inet0 grep Route
route net,-hopcount,0,,0,172.26.247.92 Route True
route net,-hopcount,0,,0,172.26.14.1 Route True
To see the default routes you have in your routing table:
# netstat -rn grep default
default 172.26.14.1 UGc 0 0 en0 - - =>
default 172.26.247.92 UGc 0 0 en0 - -
To remove one of the default routes, use smitty and not a the route command otherwise you will end up with 2 default routes after a reboot.
----------------------------------------------------------------------------------------------------------------
29. EFix - How to manage ?
To list efix :
# emgr –l
To install an efix package:
# emgr -e efixPackage
----------------------------------------------------------------------------------------------------------------
30. Kernel Processes in AIX: An Overview
# ps -kl
# pstat -a (as root)
There are several kprocs, and they do a number of things. Often they have fixed priority and will run ahead of any user processes.
A couple are:
Kproc Kernel (wait) wait process
Kproc Kernel (lrud) Least Recently Used Daemon (mem mgmt)
Kproc Kernal (swapper) Memory/Process swapping ?
Kproc Kernel (kbiod) Kernel Block I/O daemon (disk I/O)?
kproc Kernel ( gil) 1032 Networking off-level stuff
Kproc Kernel (netm) Network memory allocator
Kproc Kernel (aump) Automounter
A kproc is a kernel process, started by the kernel on behalf of either another kernel process, or as a result of an application initiating a system call or call to a kernel service.
Wait - You will find that the "wait" kproc will have accumulated a lot of cpu time. This just means your system is idle a lot. When nothing else needs to run, the wait kproc is charged the time slice
GIL - "Global ISR List"
ISR->Interrupt Service Routines - multithreaded kproc runs at fixed pri of 37 Used to process various timers (tcp, streams, ....) and also used to pass packets from demux layer to IP layer for non-CDLI drivers.
ps -lk
The processes with nice value of -- are running with fixed priorities. Their nice values can not be changed. On my system that would processes such as swapper (pid=0, pri=16) and the wait kproc (pid=514, pri=127).
This will list out all the kprocs. Now do a pstat -a to find what they really are?
This will show you the real name of the kproc.
Aump kernel thread is left over after you stop the automounter daemon.
Yes. It goes away after reboot. However, there is an APAR for it: IY33240
----------------------------------------------------------------------------------------------------------------
31. How to manage network tuning parameters in AIX ?
The no command is used to configure network tuning parameters in IBM AIX. The no command sets or displays current or next boot values for network tuning parameters. This command can also make permanent changes or defer changes until the next reboot.
Syntax:
no [ -p -r ] { -o Tunable[=NewValue] }
no [ -p -r ] {-d Tunable }
no [ -p -r ] { -D }
no [ -p -r ] -a
no -h [ Tunable ]
no -L [ Tunable ]
no -x [ Tunable ]
where:
-a : displays current, reboot or permanent value for all tunable parameters
-d : resets Tunable its to default value
-D : resets all tunables to their default value
-h : displays help about Tunable parameter
-L : lists the characteristics of one or all Tunables
-o : displays the value or sets the Tunable to NewValue
-p : makes changes apply to both current and reboot values (I heard this option in many interviews)
-r : makes changes apply to reboot values (I heard this option in many interviews)
-x : lists characteristics of one or all tunables using spreadhset format
Example to set the value of tunable tcp_sendspace to 65536 permanently:
# no -p -o tcp_sendspace=65536
Example to set the value of tunable sb_max to 2097152 at next reboot:
# no -r -o sb_max=2097152
Example to display all values of tunables:
# no -a
Example to display all values of tunables at next reboot:
# no -r -a
Example to set the value of tunable tcp_sendspace to 65536:
# no -o tcp_sendspace=65536
----------------------------------------------------------------------------------------------------------------
32. How to verify your ntp setup is working properly ?
# ntpq -c peersremote refid st t when poll reach delay offset disp =========================================================================
*time.domain.co doghaus.cns.uto 3 u 12 64 177 1.46 -2.515 145.19
If you have a star (*) in the first column of the name of the time server, your time is being synchronised properly.
The third column, st, is the stratum. The lower the number, the closer you are to the time source.
Stratum 16 means you are not synchronised.
----------------------------------------------------------------------------------------------------------------
33. How to synchronize your server time to a time server ?
If you don't want to run NTP (network time protocol), you can update your system time with the command:
# ntpdate timeserver.domain.com
----------------------------------------------------------------------------------------------------------------
34.How to list open files ?
To list all open files:
# lsof
To list all open files on a device:
# lsof /dev/hd4
----------------------------------------------------------------------------------------------------------------
35. How to find the world-wide name (WWN) or network address of a fibre-channel (FC) card in IBM AIX ?
First find the name of your fibre-channel cards:
# lsdev -vp grep fcs
Then get the WWN (for fcs0 in this example):
# lscfg -vp -l fcs0 grep "Network Address"
----------------------------------------------------------------------------------------------------------------
36. How to change a server hostname with the uname command in IBM AIX ?
To display the current hostname
# uname -n
localhost
To change the hostname
# uname -S newhostname
Again display the hostname
# uname -n
newhostname
----------------------------------------------------------------------------------------------------------------
37. How can you find out when a system was installed?
Enter the following command:
lslpp -h bos.rte
The output of this command will show the history of when the operating system was installed. Read the entry for the AIX level (ie, 4.3.3.0).
----------------------------------------------------------------------------------------------------------------
38. How to make sure all of the user definitions are correct in the user database
#usrck -n ALL
Do the same for the groups:
#grpck -n ALL
----------------------------------------------------------------------------------------------------------------
39. Reduce the Size of a File System in Your Root Volume Group ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_baseadmn_rootvg_reduce.htm#baseadmn_rootvg_reduce
----------------------------------------------------------------------------------------------------------------
40.How to reset an Unknown Root Password ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_baseadmn_recoverrootpswd.htm#baseadmn_recoverrootpswd
----------------------------------------------------------------------------------------------------------------
41. How to configure Domain Name Servers ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_commadmn_dns.htm#commadmn_dns
-----------------------------------------------------------------------------------------------------------------
42. How to re-create corrupted boot image ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_baseadmn_bad_boot_img.htm#baseadmn_bad_boot_img
----------------------------------------------------------------------------------------------------------------
43. How to configure NIM master server using EZNIM ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto/HT_insgdrf_configure_eznim.htm#insgdrf_configure_eznim
----------------------------------------------------------------------------------------------------------------
44. How do I use network (For normal users)
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/Use_Network_U.htm#category_use_network
----------------------------------------------------------------------------------------------------------------
45. How do I view system and environment information?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/AccessSys_Envir_U.htm#category_accesssys_envir
----------------------------------------------------------------------------------------------------------------
46. How do I use shell scripts ?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/Use_Shells_U.htm#category_use_shells
----------------------------------------------------------------------------------------------------------------
47. How do I redirect standard input, output, and error?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/RedirStand_IO_Error_U.htm#category_redirstand_io_error
------------------------------------------------------------------------------------------------
48. How do I make my system more secure?
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/howto_user/Security_U.htm#category_security
----------------------------------------------------------------------------------------------------------------
49. How to configure network adapters for Redundancy ?
http://users.ca.astound.net/~baspence/AIXtip/etherchannel.htm
50. Useful link about AIX Error Log codes, LED codes, 7-Digit Error codes.
http://rainsux.dyndns.org/AIX5L-Messages-Codes.html
----------------------------------------------------------------------------------------------------------------
51. How to disable remote root login ?
When multiple users have root access to a system, a common security question is who logged in as root? One alternative is to disable remote logins for the root id (chuser -rlogin=false root). This forces users to first login in with their regular user id, then "su -" to root. All "su" activity is captured in /var/adm/sulog, thus answering the question of "who logged in as root."
Comment: In general it is a good practice to disable root remote access as it provides two layers of password protection.
----------------------------------------------------------------------------------------------------------------
52. Replacing a disk drive in AIX.
http://users.ca.astound.net/~baspence/AIXtip/download/failed_disk.pdf
----------------------------------------------------------------------------------------------------------------
53. How to enabling Non-root Users to Administer Passwords ?
The AIX pwdadm command can be used to offload password administration to non-root administrators. The pwdadm command allows the administrator to change anothers password, or force users to change their password at the next login. To enable a non-root administrator to use pwdadm, simply add their ID to the "security" group.
For more information:
http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/cmds/aixcmds4/pwdadm.htm
----------------------------------------------------------------------------------------------------------------
54. Fun with device locations
Here are a few commands to locate physical devices. These commands are useful in a partitioned environment where locations are virtual.
lsdev -Cc adapter -s pci - list all adapter slots lsdev -p adapter - lists devices owned by an adapter lsdev -Cl adapter -F parent lists the parent adapter for a device (like a disk drive) lsdev -Cl adapter - virtual device location (for LPARs) lscfg -vl adapter - actual device location So, for example, to locate the physical adapter connected to hdisk0:
# Identify the parent adapterlsdev -Cl hdisk0 -F parent
# Locate the parent adapter lscfg -vl parent----------------------------------------------------------------------------------------------------------------
55. How to automate setting passwords ?
The "chpasswd" command is easier to use than "passwd" when setting a list of user passwords. It can be used from the command line or shell script. For example, to change passwords for users listed in a file, type the following
cat mypasswords chpasswd
Where the mypasswords file contains
user1:password1user2:password2......
For more information see the following URL
http://publib16.boulder.ibm.com/doc_link/en_US/a_doc_lib/cmds/aixcmds1/chpasswd.htm
----------------------------------------------------------------------------------------------------------------
56. How to list files if 'ls' is missing or corrupt ?
echo *
----------------------------------------------------------------------------------------------------------------
57. How to change the timezone and language in /etc/environment ?
chtz (timezone eg GMT0BST)
chlang (language eg En_GB)
----------------------------------------------------------------------------------------------------------------
58. Find large files
How do you find really large files in a file system:
find . -size +1024 -xdev -exec ls -l {} \;
The -xdev flag is used to only search within the same file system, instead of traversing the full directory tree. The amount specified (1024) is in blocks of 512 bytes.
----------------------------------------------------------------------------------------------------------------
59. Montoring a system without logging in
Let's say you have a helpdesk, where they must be able to run a script under user-id root to check or monitor a system:
First, create a script, you wish your helpdesk to run.
Modify your /etc/inetd.conf file and add:
check stream tcp wait root /usr/local/bin/script.sh
where script.sh is the script you've written.
Modify your /etc/services file and add:
check 4321/tcp
You may change the portnumber to anything you like, as long as it's not in use.
Now, you may run:
telnet [system] 4321
and your script will be magically run and it's output displayed on your screen. If the output of the script isn't displayed on your screen very long, just put a sleep command at the end of your script.----------------------------------------------------------------------------------------------------------------
60. Changing maxuproc requires a reboot?
When you change MAXUPROC (Maximum number of processes allowed per user), the smitty help panel will tell you that changes to this operating system parameter will take effect after the next system reboot.
This is wrong Help information. The change takes effect immediately, if MAXUPROC is increased. If it is decreased, then it will take effect after the next system reboot.
This help panel text from smitty will be changed in AIX 5.3. APAR IY52397.
----------------------------------------------------------------------------------------------------------------
61. Defunct processes
Defunct processes are commonly known as "zombies". You can't "kill" a zombie as it is already dead. Zombies are created when a process (typically a child process) terminates either abnormally or normally and it's spawning process (typically a parent process) does not "wait" for it (or has yet to "wait" for it) to return an exit status.
It should be noted that zombies DO NOT consume any system resources (except a process slot in the process table). They are there to stay until the server is rebooted.
Zombies commonly occur on programs that were (incompletely) ported from old BSD systems to modern SysV systems, because the semantics of signals and/or waiting is different between these two OS families.
------------------------------------------------------------------------------------------------
62. DLpar with DVD-ROM
Adding a DVD-ROM with DLpar is very easy. Removing however, can be somewhat more difficult, especially when you've run cfgmgr and devices have been configured.
This is how to remove it:
#rmdev -dl cd0
(Remove all cdrom devices found with lsdev -Cc cdrom)
#rmdev -dl ide0
Then remove the devices found with
# lsdev -C grep pci
All PCI devices still in use, can not be removed. The one not in use, is the PCI device where the DVD-ROM drive on was configured. You have to remove it before you can do a DLPAR remove operation on it.
Now do your DLPAR remove operation n HMC
------------------------------------------------------------------------------------------------
63. How do you send an attachment via mail from AIX ?
Uuencode is the answer:
uuencode [source-file] [filename].b64 mail -v -s "subject" [email-address]
For example:
# uuencode /etc/motd motd.b64 mail -v -s "Message of the day" email@hostname.comI
use the .b64 extension which gets recognized by Winzip. When you received your email in Outlook, you will have an attachment, which can be opened by Winzip.
------------------------------------------------------------------------------------------------
64. FTP umask
A way to change the default 027 umask of ftp is to change the entry in /etc/inetd.conf for ftpd:
ftp stream tcp6 nowait root /usr/sbin/ftpd -l -u 117
This will create files with umask 117 (mode 660).
Using the -l option will make sure the FTP sessions are logged to the syslogd. If you want to see these FTP messages in the syslogd output, then you should add in /etc/syslog.conf:
daemon.info [filename]
No comments:
Post a Comment