Tanti Technology

My photo
Bangalore, karnataka, India
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.

Wednesday, 17 February 2016

FAQ AIX


Contents

Backup and Restore

  1. How can I archive a directory with backup?
  2. How to exclude a directory from being backed up by the mksysb command?
  3. How can I extract a compressed tar archive under AIX?
  4. How can I restore an old version of a specific file with dsmc?
  5. How can I create a bootable DVD image from an mksysb?
  6. How can I restore single files or directories from mksysb?

Hardware and Support

  1. What is the command to analyze a dump with AIX 5L?
  2. How can I display all actually loaded kernel extensions?
  3. Can I run a 64bit kernel on my system?
  4. How can I activate the 64bit Kernel? Is it even already running??
  5. Is it possible to install AIX 5.2 or AIX 5.3 on my box?
  6. How can I list the version of an HMC?
  7. How can I list the firmware level of a p5 system?
  8. How can I create a snap suitable for IBM support?
  9. How can I figure out the managing HMC (and CSM server) of my LPAR?
  10. How can I see the allocated resources of an LPAR w/o checking on the HMC?
  11. How can I see statistics about all LPARs sharing the same resources?
  12. How to view the current SMT mode settings and processor information
  13. How can I check the NPIV adapter mappings on the client LPAR?

Network

  1. How can I create a backup ethernet adapter?
  2. How to set a static route?
  3. How can I force nfs mounts to use reserved ports?
  4. How do I set an IP alias under AIX?
  5. How can I see the the physical link status of an ethernet adapter?
  6. How can I check the status of an etherchannel?
  7. How can I start a service of the internet superserver inetd?
  8. What are the best options to mount an NFS share?
  9. Is it possible to pipe dd output to the ftp command?

Package Management

  1. How can I do a preview of an ML/TL upgrade?
  2. How can I apply an efix or ifix?
  3. How can I list filesets and versions on installation media?
  4. How can I get information about installed filesets and versions in one line?
  5. «lppchk -v» shows errors. Where can I find the cause?

Storage Management

  1. Is it possible to increase the maximum number of PPs beyond 1016?
  2. How can I figure out if a fibrechannel card is linked to a switch port?
  3. How can I create a dummy disk to reserve an hdisk number?
  4. How can I directly read out the VGDA of a PV (hdisk)?
  5. How can I unlock a SAN disk?
  6. How can I identify a generic SCSI disk for replacement?
  7. How can I change the the name of a tape device?
  8. How can I find all hdisks containing an AIX boot signature?
  9. How can I see statistics of an HBA?
  10. How can I find WWPNs of FC adapters in the SMS menu?
  11. How can I check what qdepth the kernel actually uses for a specific LUN?
  12. How can I increase a LUN on the fly?
  13. How can I set the number of logical partitions to be synchronized in parallel?
  14. How can I get rid of "ghost paths"?
  15. How do I create a mapfile to create an exact copy of a Logical Volume?
  16. How can I change the status of a removed PV back to active?

Miscellaneous

  1. How do I create users with long login names (more than 8 characters) under AIX 5.3?
  2. Can I use passwords with more than 8 (significant) characters?
  3. What are the correct settings for daylight saving time in Central Europe?
  4. Can I identify deleted files still opened by a process?
  5. How can I figure out what values are known to device attributes?
  6. How can I mount an ISO image file?
  7. How can I fix a broken /dev/ipldevice?
  8. How do I extend a dump device?

Backup and Restore

1. How can I archive a directory with backup?

tar on AIX has severe limitations. If I want to archive a directory without these limitations I think about the backup command. But what would be the syntax?
Assuming you want to backup /usr/local the tar command would be something like this:
# tar cvpf /tmp/archive.tar ./usr/local/
You could use the following backup command instead:
 # find ./usr/local/ | backup -iqvpf /tmp/archive.bff
To restore the backup you can use the restore command:
 # restore -xqvf /tmp/archive.bff
(the corresponding tar command would be tar xvpf /tmp/archive.tar)

2. How to exclude a directory from being backed up by the mksysb command?

To exclude a directory /var/testdir from being backed up by mksysb add the following line to the file /etc/exclude.rootvg:
^./var/testdir/
and start mksysb with the '-e' flag:
 # mksysb -e -i -X /dir/to/image

3. How can I extract a compressed tar archive under AIX?

First of all: You need gzip/bzip2 to be installed on your AIX box. However gnutar is not required - you could use the AIX tar as shown below:
# gzip -d -c archiv.tgz | tar xvf -
If you only want to have a deeper look into the archive, type:
# gzip -d -c archiv.tgz | tar tvf -
It's a bzip2 compressed archive - then type
# bzip2 -d -c archiv.tar.bz2 | tar xvf -

4. How can I restore an old version of a specific file with dsmc?

An old version of/etc/sudoers can be restored with a command like this:
# dsmc restore -pick -inactive /etc/sudoers

TSM Scrollable PICK Window - Restore

     #    Backup Date/Time        File Size A/I  File
        -----------------------------------------------------------------------
     1. | 02/11/09   21:31:28      27.74 KB  A   /etc/sudoers
     2. | 02/02/09   22:12:45      25.42 KB  I   /etc/sudoers
     3. | 01/28/09   22:10:38      25.00 KB  I   /etc/sudoers
     4. | 01/20/09   21:34:20      23.73 KB  I   /etc/sudoers
        0---------10--------20--------30--------40--------50--------60--------7
=Up  =Down  =Top  =Bottom  =Right  =Left
=Goto Line #  <#>=Toggle Entry  <+>=Select All  <->=Deselect All
<#:#+>=Select A Range <#:#->=Deselect A Range  =Ok  =Cancel
pick>
  • Type the one character commands listed in the three lines at the bottom of the page beside the pick> prompt to move up, move down, move to the bottom of the list, etc.
  • After you decide which day's backup you want to restore, type the number of that line beside the pick> prompt, press Enter. An x will appear in the first column of that line.
  • Then type o (the letter "O") and press Enter again.
  • TSM will begin to restore the file you selected.
    If you want to restore the file to a different folder, let's say to /tmp you can do it like this:
    # dsmc restore -pick -inactive /etc/sudoers /tmp/
    
    You can even pick more than one file from a list, e.g. from /etc/init.d:
    # cd /etc/init.d
    # dsmc restore -pick "*"
    
    TSM Scrollable PICK Window - Restore
    
         #    Backup Date/Time        File Size A/I  File
            -----------------------------------------------------------------------
         1. | 09/19/08   15:30:28       3.77 KB  A   /etc/init.d/gssd
         2. | 09/19/08   15:30:28       3.83 KB  A   /etc/init.d/haldaemon
         3. | 09/19/08   15:30:28       3.60 KB  A   /etc/init.d/halt
         4. | 09/19/08   15:30:28        360  B  A   /etc/init.d/halt.local
         5. | 09/19/08   15:30:28       4.01 KB  A   /etc/init.d/idmapd
         6. | 09/19/08   15:30:28      13.44 KB  A   /etc/init.d/ipmi
         7. | 09/19/08   15:30:28       2.12 KB  A   /etc/init.d/irq_balancer
         8. | 09/19/08   15:30:28       2.79 KB  A   /etc/init.d/joystick
         9. | 09/19/08   15:30:28      11.91 KB  A   /etc/init.d/kbd
            0---------10--------20--------30--------40--------50--------60--------7
    =Up  =Down  =Top  =Bottom  =Right  =Left
    =Goto Line #  <#>=Toggle Entry  <+>=Select All  <->=Deselect All
    <#:#+>=Select A Range <#:#->=Deselect A Range  =Ok  =Cancel
    pick>
    
  • Type the one character commands listed in the three lines at the bottom of the page beside the pick> prompt to move up, move down, move to the bottom of the list, etc.
  • After you decide which files you want to restore, type the number of that line beside the pick> prompt, press Enter. An x will appear in the first column of that line.
  • Then type o (the letter "O") and press Enter again.
  • TSM will begin to restore the files you selected.  

    5. How can I create a bootable DVD image from an mksysb?

    Let's say you have an mksysb image present under /var/backups/mksysb.obj, then you can run the following command to create a bootable DVD image from it:
     # mkcd -L -S -I /iso-images -m /var/backups/mksysb.obj
    
    In the above example the DVD image can be found under /iso-images. Please note that the switch -m doesn't accept relative paths!  

    6. How can I restore single files or directories from mksysb?

    To restore a single file - let's say /etc/mail/sendmail.cf - from mksysb, type
    # restore -xqvf mksysb.img ./etc/mail/sendmail.cf
    
    Two or more files could be restored by a line like this:
    # restore -xqvf mksysb.img ./etc/mail/aliases ./etc/mail/aliases.db
    
    And if you want to restore a whole directory with all files and subdirectories, type
    # restore -xqvf mksysb.img './etc/mail/*'
    
    The above command restores /etc/mail and all containing files.
    Please note: All files will be restored with full path relative to your current working directory.

    Hardware and Support

    1. What is the command to analyze a dump with AIX 5L?

    Since AIX 5.1 the proper command to analyze a dump is kdb. For AIX 4.3.3 and earlier you use crash instead. The usage is almost identical.

    2. How can I display all actually loaded kernel extensions?

    You use the command genkex to see all modules and extensions loaded into the kernel. If you are only interested in real extensions, you can use a line like this:
     # genkex | grep 'ext$'
    

    3. Can I run a 64bit kernel on my system?

    You can use the bootinfo command:
     # bootinfo -y
     32
    
    If it comes back with 32 this machine can not run the 64bit kernel. Does it come back with 64 it can run both, 32bit and 64bit kernel.

    4. How can I activate the 64bit Kernel? Is it even already running??

    Since AIX 5.2 the classic kernel /unix is only a link to the real kernel file in /usr/lib/boot. You can follow this link to see which kernel the system is supposed to use. In the below example this link points to /usr/lib/boot/unix_64 what means that your system is set up for a 64bit kernel. However, does this link point to either /usr/lib/boot/unix_up or/usr/lib/boot/unix_mp your system is set up to run the 32bit kernel.
    Example:
     # ls -l /unix
     lrwxrwxrwx   1 root     system           21 21 Jul 2004  /unix -> /usr/lib/boot/unix_64
    
    Use bootinfo to figure out which kernel the system actually runs:
     # bootinfo -K
     64
    
    If your system still runs the 32bit kernel and you want to change to 64bit the above link and another link unix in /usr/lib/boot have to be set accordingly:
     # cd /
     # rm -f unix
     # ln -s /usr/lib/boot/unix_64 unix
     # cd /usr/lib/boot/
     # rm -f unix
     # ln -s unix_64 unix
    
    After the new links have been set you have to rewrite all BLVs:
     # bosboot -a
    
     bosboot: Boot image is 19008 512 byte blocks.
    
    After the next reboot your system will run the 64bit kernel.

    5. Is it possible to install AIX 5.2 or AIX 5.3 on my box?

    Since AIX version 5.2 IBM does not support the whole range of power processor based RS/6000 models anymore. You can issue the command " bootinfo -p " to figure out if your system can be installed with AIX 5.2 or 5.3. Does the command come back with " chrp " your system can run AIX 5.2 or 5.3. Does the command respond " rs6k " or " rspc " however, you cannot install any version of AIX higher 5.1.
     # bootinfo -p
     chrp
    
    Please note that a firmware upgrade might be needed in order to boot from the AIX 5.2 CD!
    AIX 6.1 does not support all chrp models!. Particulary 32bit systems are not supported anymore.

    6. How can I list the version of an HMC?

    On the HMC commandline you can use lshmc to check the HMC version:
     hscroot@hmc:~> lshmc -V
     "version= Version: 5
      Release: 1.0
     HMC Build level 20051110.1
     MH00464: InfoCenter Update for V5R1.0 (10-27-2005)
     MH00493: Fixes for leap second handling, DST time and openssl (11-29-2005)
     MH00507: Maintenance Package for V5R1.0 (12-03-2005)
     "
    
    You could also use WebSM/wsm to get this information:
    1. On the left open "Licensed Internal Code Maintenance"
    2. click on "HMC Code Update"
    3. In the "Status" area you find the same information you saw with lshmc -V.
    If you want to learn more about the HMC commandline interface, you might want to have a look at the HMC Commandline Howto.

    7. How can I list the firmware level of a p5 system?

    Login to any of the LPARs of your p5 system and issue the command lsmcode:
     DISPLAY MICROCODE LEVEL                                                              802811
     IBM,9117-570
    
     The current permanent system firmware image is SF235_185
     The current temporary system firmware image is SF235_185
     The system is currently booted from the temporary firmware image.
    

    8. How can I create a snap suitable for IBM support?

    The general command to collect information for the IBM support is snap. First you should remove any old snap files. The easiest way to remove any old snap files is snap -r. To avoid problems when creating the new snap, you should also manually remove the whole subdirectory /tmp/ibmsupt:
     # rm -rf /tmp/ibmsupt
     # snap -gfiLGc
     Checking space requirement for general information........................done.
                            .
                            .
                            .
     Creating compressed pax file...
     Starting pax/compress process... Please wait... done.
    
     -rw-------   1 0        0           8621905 Mar  2 10:40 snap.pax.Z
    
    You find the compressed snap file under /tmp/ibmsupt/snap.pax.Z. This file should be sent to IBM.

    9. How can I figure out the managing HMC (and CSM server) of my LPAR?

    To find the managing servers of your LPAR you can use the domain status information - the ctrmc subsystem must be active in order to do so. You can check with:
     # lssrc  -s ctrmc
     Subsystem         Group            PID          Status
      ctrmc            rsct             1151036      active
    
    Is the subsystem indeed active you get the IP address of your HMC with:
     # /usr/sbin/rsct/bin/rmcdomainstatus -s ctrmc
    
     Management Domain Status: Management Control Points
       O A  0xccdfc3e608ad7624  0001  192.168.100.10
    
    Is your LPAR also connected to a CSM server you would see two Control Points:
     # /usr/sbin/rsct/bin/rmcdomainstatus -s ctrmc
    
     Management Domain Status: Management Control Points
       I A  0x58016857defc1b87  0001  192.168.100.11  
       I A  0xccdfc3e608ad7624  0002  192.168.100.10
    
    For newer versions of rsct you could also use lsrsrc to get this information:
     # lsrsrc -l "IBM.ManagementServer"
    Resource Persistent Attributes for IBM.ManagementServer
    resource 1:
            Name             = "192.168.100.10"
            Hostname         = "192.168.100.10"
            ManagerType      = "HMC"
            LocalHostname    = "192.168.100.23"
            ClusterTM        = "9078-160"
            ClusterSNum      = ""
            ActivePeerDomain = ""
            NodeNameList     = {"mylpar22-ext"}
    resource 2:
            Name             = "192.168.100.11"
            Hostname         = "192.168.100.11"
            ManagerType      = "CSM"
            LocalHostname    = "mylpar22"
            ClusterTM        = "9078-160"
            ClusterSNum      = "10BF571"
            ActivePeerDomain = ""
            NodeNameList     = {"mylpar22-ext"}
    

    10. How can I see the allocated resources of an LPAR w/o checking on the HMC?

    Run this command on your LPAR:
     $ lparstat -i
     Node Name                                  : barney
     Partition Name                             : mylpar2
     Partition Number                           : 2
     Type                                       : Shared-SMT
     Mode                                       : Uncapped
     Entitled Capacity                          : 0.60
     Partition Group-ID                         : 32796
     Shared Pool ID                             : 0
     Online Virtual CPUs                        : 6
     Maximum Virtual CPUs                       : 10
     Minimum Virtual CPUs                       : 1
     Online Memory                              : 3072 MB
     Maximum Memory                             : 16384 MB
     Minimum Memory                             : 1024 MB
     Variable Capacity Weight                   : 80
     Minimum Capacity                           : 0.10
     Maximum Capacity                           : 10.00
     Capacity Increment                         : 0.01
     Maximum Physical CPUs in system            : 16
     Active Physical CPUs in system             : 8
     Active CPUs in Pool                        : 8
     Unallocated Capacity                       : 0.00
     Physical CPU Percentage                    : 10.00%
     Unallocated Weight                         : 0
    

    11. How can I see statistics about all LPARs sharing the same resources?

    There is a special option in topas that allows you to see CPU and Memory usage of the whole CEC:
     # topas -C
    
    The output is something like this:
     Topas CEC Monitor             Interval:  10             Wed Aug 13 17:08:13 2008
     Partitions Memory (GB)           Processors
     Shr: 12    Mon:83.0  InUse:20.6  Shr:3.8  PSz:  8   Don: 0.0 Shr_PhysB  0.14
     Ded:  0    Avl:   -              Ded:  0  APP:  7.9 Stl: 0.0 Ded_PhysB  0.00
    
     Host         OS  M Mem InU Lp  Us Sy Wa Id  PhysB  Vcsw Ent  %EntC PhI
     -------------------------------------shared-------------------------------------
     vioserver1   A53 U 5.0 1.4  6   3  6  0 90   0.03  177  0.30  10.3   2
     vioserver2   A53 U 5.0 1.2  6   3  6  0 90   0.03  257  0.30  10.1   2
     mylpar0      A53 U 5.0 3.1  6   2  4  0 92   0.02  195  0.30   7.6   0
     mylpar1      A53 U 5.0 2.8  6   0  2  0 96   0.01  363  0.30   4.0   0
     mylpar2      A53 U  10 1.5 12   0  0  0 99   0.01  367  0.60   1.2   1
     mylpar3      A53 U  18 2.7  8   0  0  0 98   0.01  288  0.40   1.7   0
     mylpar4      A53 U 6.0 1.3  2   0  3  0 96   0.01  190  0.10   5.1   0
     mylpar5      A53 U 3.0 1.5 12   0  0  0 99   0.01  286  0.60   0.8   0
     mylpar6      A53 U  10 1.5 12   0  0  0 99   0.00  231  0.60   0.8   0
     mylpar7      A53 U 6.0 1.2  2   0  2  0 97   0.00  176  0.10   4.1   2
     mylpar8      A53 U 6.0 1.3  2   0  1  0 97   0.00  135  0.10   3.2   0
     mylpar9      A53 U 4.0 1.1  2   0  1  0 97   0.00  132  0.10   3.1   0
     Host         OS  M Mem InU Lp  Us Sy Wa Id  PhysB  Vcsw  %istl %bstl
     Host         OS  M Mem InU Lp  Us Sy Wa Id  PhysB  Vcsw  %istl %bstl------------
     ------------------------------------dedicated-----------------------------------
    

    12. How to view the current SMT mode settings and processor information

    You can use smtctl to get the information. Below is an example:
    # smtctl
    
    This system is SMT capable.
    
    SMT is currently enabled.
    
    SMT boot mode is not set.
    SMT threads are bound to the same virtual processor.
    
    proc0 has 2 SMT threads.
    Bind processor 0 is bound with proc0
    Bind processor 1 is bound with proc0
    
    
    proc2 has 2 SMT threads.
    Bind processor 2 is bound with proc2
    Bind processor 3 is bound with proc2
    

    13. How can I check the NPIV adapter mappings on the client LPAR?

    With AIX 6.1 and higher you can use kdb to see the mapings on the client:
    # echo "vfcs" | kdb | grep -E '^NAME|^fcs'
    NAME      ADDRESS             STATE   HOST      HOST_ADAP  OPENED NUM_ACTIVE
    fcs0      0xF1000A0000186000  0x0008  vioserver1vfchost1  0x01    0x0000
    fcs1      0xF1000A0000188000  0x0008  vioserver2vfchost1  0x01    0x0000
    fcs2      0xF1000A000018A000  0x0008  vioserver1vfchost2  0x01    0x0000
    fcs3      0xF1000A000018C000  0x0008  vioserver2vfchost2  0x01    0x0000
    fcs4      0xF1000A001DB06000  0x0008  vioserver1vfchost3  0x01    0x0000
    fcs5      0xF1000A000018E000  0x0008  vioserver2vfchost3  0x01    0x0000
    fcs6      0xF1000A0000180000  0x0008  vioserver1vfchost4  0x01    0x0000
    fcs7      0xF1000A001DB02000  0x0008  vioserver2vfchost4  0x01    0x0000
    

    14. How can I find the serial number of my POWER machine?

    # lscfg -vp | grep -p "System VPD" | fgrep "Machine/Cabinet Serial No"
               Machine/Cabinet Serial No...063TD8T
    

    Network

    1. How can I create a backup ethernet adapter?

    You have to create an etherchannel device. First you have to unconfigure the current ethernet settings on the physical ethernet adapter (en0 in the below example). You also need to make sure that there is a second physical ethernet adapter available (en1 in the below example). If these requirements are met you create the etherchannel with the commands below:
     # ifconfig en0 detach
     # chdev -P -l en0 -a state=down
     # mkdev -c adapter -s pseudo -t ibm_ech -a adapter_names=ent0 \
         -a backup_adapter=ent1 -a netaddr=192.168.100.1 \
         -a num_retries=3 -a retry_time=3
     # mkdev -c if -s EN -t en -a netaddr=192.168.100.33 \
         -a netmask=255.255.255.0 -w en2 -a state=up -a arp=on
     # mkdev -l inet0
    
    The IP address of the first mkdev call belongs to a host (e.g. the gateway) that can be pinged. The system uses this to figure out if the primary network adapter is still alive. The secondmkdev however, defines the IP address you want to set to your new etherchannel logical device (i.e. the communication IP address of the box). The system uses the next free number for the etherchannel device (in our example en2).

    2. How to set a static route?

    Of course you can use the route command to set a static route. But this way you don't get it back after reboot.
    To make a route persistent you need to change inet0. First check which routes are already set:
     # lsattr -El inet0 -a route
     route net,-hopcount,0,,0,192.168.1.1 Route True
     route net,-hopcount,255.255.255.128,,,,,192.168.3.155,192.168.2.1 Route True
    
    These routes would be set with:
     # chdev -l inet0 -a route=net,-hopcount,0,,0,192.168.1.1
     # chdev -l inet0 -a route=net,-hopcount,255.255.255.128,,,,,192.168.3.155,192.168.2.1
    
    To remove these specific static routes:
     # chdev -l inet0 -a delroute=net,-hopcount,0,,0,192.168.1.1
     # chdev -l inet0 -a delroute=net,-hopcount,255.255.255.128,,,,,192.168.3.128,192.168.2.1
    
    In this route string 255.255.255.128 is the netmask, 192.168.3.128 the destination net, and 192.168.2.1 the gateway.
    For hostroutes the keyword net has to be replaced with host.

    3. How can I force nfs mounts to use reserved ports?

    Some UNIX variants such as OpenBSD or Solaris require clients to use reserved ports (below 1024) to mount nfs shares. But AIX uses non-reserved by default when trying to mount an nfs share. However, with the following command you can change the default:
     # nfso -o nfs_use_reserved_ports=1
    
    The above command will lose effect after reboot. To make it permanent you use the '-p' switch on AIX 5L and 6:
     # nfso -p -o nfs_use_reserved_ports=1
    
    This setting is also respected by the autofs subsystem. But be aware that this setting has to be made before a remote filesystem is actually mounted!

    4. How do I set an IP alias under AIX?

    To put a second IP address to en0, just use ifconfig:
    # ifconfig en0 192.168.100.199 netmask 255.255.255.0 alias
    
    This sets an additional IP address 192.168.100.199 to en0. Of course, if you use ifconfig to set an IP alias, the alias won't be present after the next reboot. To make the setting permanent, you have to change the interface's definition in the ODM. The SMIT fastpath is mkinet4al. If you prefer to use the commandline, type:
    # chdev -l en0 -a alias4="192.168.100.199,255.255.255.0"
    
    You can remove an IP alias with a comand like this:
    # ifconfig en0 delete 192.168.100.199
    
    No need to use the keyword 'alias' here. To delete the IP address permanently you can use chdev again:
    # chdev -l en0 -a delalias4="192.168.100.199,255.255.255.0"
    

    5. How can I see the the physical link status of an ethernet adapter?

    You can run entstat -d on the physical adapter and search for media speed and link status:
    # entstat -d ent0 | egrep "(Link Status|Media Speed)"
    Link Status : Up
    Media Speed Selected: Auto negotiation
    Media Speed Running: 1000 Mbps Full Duplex
    

    6. How can I check the status of an etherchannel?

    Run entstat -d command on the etherchannel device and search for Link StatusActive channel, and Physical Port Link State. If you use a backup adapter check also for Backup adapter. To get the information in one view you could run a command like this:
    # entstat -d ent6 | egrep "(Link Status|Active channel|Physical Port Link State|Backup adapter|\(ent.\)|\(ent..\))"
    ETHERNET STATISTICS (ent6) :
    Active channel: primary channel
    ETHERNET STATISTICS (ent3) :
    Link Status : Up
    Backup adapter - ent5:
    ETHERNET STATISTICS (ent5) :
    Link Status : Up
    

    7. How can I start a service of the internet superserver inetd?

    For example - if you want to enable the ftp service just type
    # startsrc -t ftp
    0513-124 The ftp subserver has been started.
    
    To stop the ftp service again type
    # stopsrc -t ftp
    0513-127 The ftp subserver was stopped successfully.
    
    No need to manually edit /etc/inetd.conf!
    You can check the current status of the inetd with
    # lssrc -ls inetd 
    

    8. What are the best options to mount an NFS share?

    I assume you want the nfs share to be automatically present after a system restart. Then you can use the below command to mount a share /nas/diska/vol1 from the servernas.unixwerk.eu to /import/nas_vol1:
    # mknfsmnt -d /nas/diska/vol1 -h nas.unixwerk.eu -f /import/nas_vol1 -b 32768 -c 32768 -A -H -E 
    
    And that's how it looks in /etc/filesystems:
    /import/nas_vol1:
            dev             = "/nas/diska/vol1"
            vfs             = nfs
            nodename        = nas.unixwerk.eu
            mount           = true
            options         = hard,intr,rsize=32768,wsize=32768,timeo=600
            account         = false
    
    The options in the above example are my choices for mounting NAS volumes. If you want to mount the share read-only you can add -t ro to the above command. If you want to only add a stanza to /etc/filesystems without already mounting the share you can add the option -I to the command:
    # mknfsmnt -t ro -d /nas/diska/vol1 -h nas.unixwerk.de -f /import/nas_vol1 -b 32768 -c 32768 -A -H -E -I
    

    9. Is it possible to pipe dd output to the ftp command?

    Yes, it's possible:
    # ftp server.com
    ftp> bin
    ftp> put "|dd if=/dev/zero bs=32k count=10000" /dev/null
    
    The above ftp command reads from /dev/zero on the local side and writes to /dev/null on the remote side. This prevents both the local and the remote system from involving disks.

    Package Management

    1. How can I do a preview of an ML/TL upgrade?

    If I want to upgrade an AIX system to a new ML or TL I like to check it first by doing an PREVIEW only. But the result of this action is not very helpful, because I always see that only one fileset will be updated, all the rest is rejected because of dependency failures. However when I start the real update all the other filesets will be upgraded aswell, although the PREVIEW said different.
    You have to upgrade the installer separately first (APPLY only). This can be done with a command like this:
     # cd /path/to/TL
     # installp -agX -d. bos.rte.install
    
    Restart the upgrade procedure:
     # smitty update_all
    
    Now you can do a PREVIEW only installation and you see which filesets actually would be upgraded. If you decide to not upgrade the system after the preview you can easily roll back the installer to the old version with:
     # smitty reject
    

    2. How can I apply an efix or ifix?

    You don't apply interim fixes (ifix) or emergency fixes (efix) with installp - instead you do it with the Efix Manager. IBM provides these fixes in a compressed epkg format (suffix: .epkg.Z). And that's how it's been applied:
    # emgr -e .epkg.Z
    
    You get a list of all installed fixes with
    # emgr -l
    
    ID  STATE LABEL    INSTALL TIME      UPDATED BY ABSTRACT
    === ===== ======== ================= ========== ================
    1    S    IZ79677  09/16/10 16:09:52            iFix for IZ79677
    
    The Label from the table above is needed when you ever want to remove an efix from the system:
    # emgr -r -L 
    
    With a TL or SP upgrade installp will automatically remove an interim fix only if the service pack already contains it. If not the upgrade will fail and you have to remove it with the efix manager before upgrading.

    3. How can I list filesets and versions on installation media?

    I want to know what filesets are present on installation media or a on a directory where I put some files with not human readable names (such as U838402.bff). How can I get the information?
    # cd /path/to/bffs
    # installp -l -d .
      Fileset Name                Level                     I/U Q Content
      ====================================================================
      Java5.samples               5.0.0.275                  I  N usr
    #   Java SDK 32-bit Samples
    
      Java5.sdk                   5.0.0.325                  I  N usr,root
    #   Java SDK 32-bit
    
      Java5.source                5.0.0.325                  I  N usr
    #   Java SDK 32-bit Source
    
      Java5_64.sdk                5.0.0.325                  I  N usr,root
    #   Java SDK 64-bit
    
      Java6.sdk                   6.0.0.215                  I  N usr,root
    #   Java SDK 32-bit
    
    The same way you can display the package name of a single fileset:
    # installp -l -d U839870.bff
      Fileset Name                Level                     I/U Q Content
      ====================================================================
      devices.chrp.base.ServiceRM 1.5.0.1                    S  N usr,root
    #   RSCT Service Resource Manager
    
    Please note: Using installp requires a .toc file to be present. This is always the case on official media. However, if you downloaded some update filesets the .toc file might be missing. Not a problem - just create it with the inutoc command:
    # cd /path/to/bffs
    # inutoc .
    

    4. How can I get information about installed filesets and versions in one line?

    When I want to list filesets installed on my LPAR I can use "lslpp -l" or "lslpp -L". But the first gives me separate output for root and /usr part of a fileset - the latter breaks lines with long descriptions. Is there something else?
    You can display the information as a list separated by colons. Fileset name, version, and descriptions are stored in the fields 2, 3, and 8 respectrively. Here is an example:
    # lslpp -Lqc bos.net.nfs.\* | cut -d: -f2,3,8
    bos.net.nfs.client:6.1.4.4:Network File System Client
    bos.net.nfs.server:6.1.4.0:Network File System Server
    

  • «lppchk -v» shows errors. Where can I find the cause?

    5. «lppchk -v» shows errors. Where can I find the cause?

    After an AIX migration everything seems to be fine. However «lppchk -v» shows an error such as below:
    # lppchk -v
    lppchk:  The following filesets need to be installed or corrected to bring
             the system to a consistent state:
    
      rsct.core.rmc v=2, r<5 fileset="" installed="" not="" pre="" requisite="">
    The error descriptions does not help much. It does not show which fileset's dependencies are actually violating the consistence of the package database. However we can search the ODM for filesets with such a dependency:
    # odmget product|fgrep -p 'rsct.core.rmc v=2 r<5 b="">
    product:
            lpp_name = "sam.core.rte"
            comp_id = ""
            update = 0
            cp_flag = 275
            fesn = ""
            name = "sam.core"
            state = 5
            ver = 3
            rel = 2
            mod = 0
            fix = 0
            ptf = ""
            media = 3
            sceded_by = ""
            fixinfo = ""
            prereq = "*prereq rsct.core.utils 2.4.13.1\n\
    *prereq rsct.core.rmc v=2 r<5 b="">\n\
    *prereq rsct.basic.rte 2.4.13.1\n\
    "
            description = "SA CHARM Runtime Commands"
            supersedes = ""
    
    Conclusion: The fileset «sam.core.rte» has such a dependency. If you run in such a problem consider to update the fileset causing the error or check if the fileset is needed at all.

    Storage Management

    1. Is it possible to increase the maximum number of PPs beyond 1016?

    If you want to integrate a new and larger disk into an existing Volume Group you might run into problems with the the maximum number of PPs of one Physical Volume. The reason is, that when creating a new Volume Group the PP size is often set to the smallest value possible. The number of PPs/PV of a standard Volume Group is limited to 1016. What to do?
    You can use chvg -t to increase the number of PPs with a factor of 2,4,16, or 32:
     # chvg -t 2 rootvg
    
    With the above command you increase the maximum number of PPs per PV in the rootvg to 2032. But be aware, that you decrease the number of PVs (hdisks) per VG with the same factor. In this example the rootvg cannot contain more then 16 PVs.

    2. How can I figure out if a fibrechannel card is linked to a switch port?

    Check the status of the FC SCSI I/O Controller Protocol Device:
    The below example shows the status of the FC SCSI I/O Controller Protocol Device of the first fibre channel adapter if the system is not connected to the switch (cable is present, but switch port not configured) - attach: none, no SCSI ID:
     # lsattr -El fscsi0
     attach       none         How this adapter is CONNECTED         False
     dyntrk       no           Dynamic Tracking of FC Devices        True
     fc_err_recov delayed_fail FC Fabric Event Error RECOVERY Policy True
     scsi_id                   Adapter SCSI ID                       False
     sw_fc_class  3            FC Class for Fabric                   True
    
    ... and this is how it looks, if the card is connected to the switch:
     # lsattr -El fscsi1
     attach       switch       How this adapter is CONNECTED         False
     dyntrk       no           Dynamic Tracking of FC Devices        True
     fc_err_recov delayed_fail FC Fabric Event Error RECOVERY Policy True
     scsi_id      0x610100     Adapter SCSI ID                       False
     sw_fc_class  3            FC Class for Fabric                   True
    
    ... and this is how it looks if there is no cable to a switch at all:
     # lsattr -El fscsi1
     attach       al           How this adapter is CONNECTED         False
     dyntrk       no           Dynamic Tracking of FC Devices        True
     fc_err_recov delayed_fail FC Fabric Event Error RECOVERY Policy True
     scsi_id      0x610100     Adapter SCSI ID                       False
     sw_fc_class  3            FC Class for Fabric                   True
    
    al means Arbitrary Loop. You get this if there is no cable plugged into the fibre channel card. But you also get this if the system is directly attached to a storage box (e.g. FAStT). In the latter case there is nothing wrong if you see attach: al

    3. How can I create a dummy disk to reserve an hdisk number?

    Below you find a situation where the next LUN that is mapped to your system would get an hdisk number 0 (hdisk0):
     # lsdev -Cc disk
     hdisk1 Available 06-08-00-4,0 16 Bit LVD SCSI Disk Drive
     hdisk2 Available 06-08-00-5,0 16 Bit LVD SCSI Disk Drive
    
    To avoid this you could reserve hdisk0 for a dummy disk, e.g.:
     # mkdev -l hdisk0 -c disk -t osdisk -s scsi -p scsi0 -w 0,10 -d
     hdisk0 defined
    
    Now we see hdisk0 as defined:
     # lsdev -Cc disk
     hdisk0 Defined   06-08-00-0,10 Other SCSI Disk Drive
     hdisk1 Available 06-08-00-4,0  16 Bit LVD SCSI Disk Drive
     hdisk2 Available 06-08-00-5,0  16 Bit LVD SCSI Disk Drive
    
    ... and the next LUN would be mapped to hdisk3.
    Unfortunately this trick only works for systems with a SAS controller assigned. With AIX 5.3 you still have the option to create a dummy SSA disk:
     # mkdev -l hdisk0 -p ssar -t hdisk -w dummy
     mkdev: 0514-519 The following device was not found in the customized
             device configuration database:
             name='ssar'
    
    Don't be confused by the error - we have a hdisk0 now:
     # lsdev -Cc disk
     hdisk0 Defined                SSA Logical Disk Drive
     hdisk1 Available 06-08-00-4,0 16 Bit LVD SCSI Disk Drive
     hdisk2 Available 06-08-00-5,0 16 Bit LVD SCSI Disk Drive
    
    This complicated procedure is not needed any more since AIX 7.1 and AIX 6.1 TL6 - a new command has been made available:
     # lspv
     hdisk0          00c8b12ce3c7d496                    rootvg          active
     hdisk1          00c8b12cf28e737b                    None
     # rendev -l hdisk1 hdisk99
     # lspv
     hdisk0          00c8b12ce3c7d496                    rootvg          active
     hdisk99         00c8b12cf28e737b                    None
    

    4. How can I directly read out the VGDA of a PV (hdisk)?

    Information about VGx, LVx, filesystems, etc. are stored in the ODM. But these information are also written to the VGDA of the disks itself. You can read the information directly from the disk's VGDA with a command like this:
    # lqueryvg -Atp hdisk100
    
    You can use
    # redefinevg -d hdisk100 myvg
    
    to synchronize the ODM with the information of the VGDA. You can also synchronize the VGDA with the information stored in the ODM:
    # synclvodm myvg
    

    5. How can I unlock a SAN disk?

    Finally I got my LUN mapped to my system, but when I try to create my Volume Group with   mkvg -f vpath100   all I get is an I/O error. What can I do?
    Probably there is still a SAN lock on the disk. For vpath devices try to unlock it with:
    # lquerypr -ch /dev/vpath100
    
    and retry to create your Volume Group. If you use the newer sddpcm drivers the command to unlock would be
     # pcmquerypr -ch /dev/hdisk100
    

    6. How can I identify a generic SCSI disk for replacement?

    To identify a SCSI disk (attached to a hot swap enclosure) with AIX you can use diag to let it blinking:
    # diag
    
    Then select
     > Task Selection (Diagnostics, Advanced Diagnostics, Service Aids, etc.)
             > Hot Plug Task
                     > SCSI and SCSI RAID Hot Plug Manager
                             > Identify a Device Attached to a SCSI Hot Swap Enclosure Device
    
    You see the following screen providing you with a list of hdisks. Select the one you need to identify:
    IDENTIFY DEVICE ATTACHED TO SCSI HOT SWAP ENCLOSURE DEVICE
    
    The following is a list of devices attached to SCSI Hot Swap Enclosure devices.
    Selecting a slot will set the LED indicator to Identify.
    
    Make selection, use Enter to continue.
    
    
                    U0.1-
      ses2            P1-I1/Z1-Af
         slot  1      P1-I1/Z1-A8          hdisk2
         slot  2      P1-I1/Z1-A9          hdisk3
         slot  3      P1-I1/Z1-Aa          hdisk4
         slot  4      P1-I1/Z1-Ab          hdisk5
         slot  5      P1-I1/Z1-Ac          hdisk6
         slot  6      P1-I1/Z1-Ad          hdisk7
         slot  7      P1-I1/Z1-Ae          hdisk8
    
                    U0.1-
      ses3            P1-I5/Z1-Af
         slot  1      P1-I5/Z1-A0          hdisk9
         slot  2      P1-I5/Z1-A1          hdisk10
         slot  3      P1-I5/Z1-A2          hdisk11
         slot  4      P1-I5/Z1-A3          hdisk12
         slot  5      P1-I5/Z1-A4          hdisk13
         slot  6      P1-I5/Z1-A5          hdisk14
         slot  7     +------------------------------------------------------+
                     |                                                      |
                     | The LED should be in the Identify state for the      |
                     | selected device.                                     |
                     |                                                      |
                     | Use 'Enter' to put the device LED in the             |
                     | Normal state and return to the previous menu.        |
                     |                                                      |
                     | F3=Cancel        F10=Exit         Enter              |
                     +------------------------------------------------------+
    F1=Help                 F10=Exit
    
    
    If you already removed the hdisk with the rmdev command you would still see the slot in the above screen but no device name.

    7. How can I change the the name of a tape device?

    You can rename a tape device (i.e. rmtX or smcX) easily with chdev. For example, if you want to rename rmt0 to rmt201 just type:
    # chdev -l rmt0 -a new_name=rmt201
    rmt0 changed
    
    Please note: It only works with tapes! This is because IBM defined a special attribute new_name in the ODM only for tape drives and media changers.
    Update: AIX 7.1 and AIX 6.1 T6 introduced a new command rendev that can be used to rename any device. The below command would rename ent0 to ent99:
    # rendev -l ent0 -n ent99
    

    8. How can I find all hdisks containing an AIX boot signature?

    # ipl_varyon -i
    
    
    PVNAME          BOOT DEVICE     PVID                                    VOLUME GROUP ID
    hdisk0          YES             00f64183e8ff11c50000000000000000        00f6418300004c00
    hdisk1          NO              00f6418384f345d00000000000000000        00f6418300004c00
    hdisk2          NO              00f6418384f346210000000000000000        00f6418300004c00
    hdisk3          NO              00f6418384f3466c0000000000000000        00f6418300004c00
    hdisk4          NO              00f6418384f346b00000000000000000        00f6418300004c00
    hdisk5          NO              00f6418384f346f20000000000000000        00f6418300004c00
    hdisk6          NO              00f6418384f44fca0000000000000000        00f6418300004c00
    hdisk7          NO              00f6418384f450150000000000000000        00f6418300004c00
    hdisk8          NO              00f6418384f450540000000000000000        00f6418300004c00
    hdisk9          NO              00f6418384f4508f0000000000000000        00f6418300004c00
    hdisk10         NO              00f6418384f450ca0000000000000000        00f6418300004c00
    hdisk11         NO              00f6418384f347390000000000000000        00f6418300004c00
    hdisk12         NO              00f6418384f450ff0000000000000000        00f6418300004c00
    
    Conclusion: Only hdisk0 contains a boot signature.

    9. How can I see statistics of an HBA?

    Use the fcstat command on the FC adapter:
    # fcstat fcs0
    
    The command gives a whole page of output not shown here. The command shows statistics similar to the entstat command. If you are only interested in the port speed, you could type
    # fcstat fcs0 | grep 'Port Speed'
    Port Speed (supported): 8 GBIT
    Port Speed (running):   4 GBIT
    

    10. How can I find WWPNs of FC adapters from the SMS menu?

    It is possible to find the WWPNs in the OpenFirmware Prompt - at least on recent hardware. From the HMC boot the LPAR into the Open Firmware Prompt and issue the ioinfo command at the ok-prompt:
              1 = SMS Menu                          5 = Default Boot List
              8 = Open Firmware Prompt              6 = Stored Boot List
    
    
         Memory      Keyboard     Network     SCSI     Speaker
    
    0 > ioinfo
    
    !!! IOINFO: FOR IBM INTERNAL USE ONLY !!!
    This tool gives you information about SCSI,IDE,SATA,SAS,and USB devices attached to the system
    
    Select a tool from the following
    
     1. SCSIINFO
     2. IDEINFO
     3. SATAINFO
     4. SASINFO
     5. USBINFO
     6. FCINFO
     7. VSCSIINFO
    
    q - quit/exit
    
    ==> 6
    
    
    
    FCINFO Main Menu
    Select a FC Node from the following list:
      #  Location Code                Pathname
    ---------------------------------------------------------------
      1. U5877.001.0082113-P1-C10-T1    /pci@80000002000012b/fibre-channel@0
      2. U5877.001.0082113-P1-C10-T2    /pci@80000002000012b/fibre-channel@0,1
      3. U5877.001.0082924-P1-C10-T1    /pci@80000002000013b/fibre-channel@0
      4. U5877.001.0082924-P1-C10-T2    /pci@80000002000013b/fibre-channel@0,1
    
      q - Quit/Exit
    
    ==> 1
    
    FC Node Menu
    FC Node String: /pci@80000002000012b/fibre-channel@0
    FC Node WorldWidePortName: 10000000c9d08fd0 
    -----------------------------------------------------------------
    1. List Attached FC Devices
    2. Select a FC Device
    3. Enable/Disable FC Adapter Debug flags
    
    q - Quit/Exit
    
    Conclusion: The WWPN of the first port of the first FC adapter is: 10000000c9d08fd0. On a running AIX system you would find the same information with
    # lscfg -vpl fcs0 | grep 'Network Address'
            Network Address.............10000000C9D08FD0
    

    11. How can I check what qdepth the kernel actually uses for a specific LUN?

    It's easy to set the qdepth with chdev as it is easy to read it out with lsattr:
     # chdev -l hdisk100 -a queue_depth=8
     hdisk100 changed
     # lsattr -El hdisk100 -a queue_depth
     queue_depth 8 Queue DEPTH True
    
    But it's not possible to change the qdepth as long as the hdisk is in use. But you could still change the value in the ODM and wait for the next reboot for the change to apply. But here we have a problem. lsattr already shows the new value while the kernel still uses the old one.
     # lsattr -El hdisk100 -a queue_depth
     queue_depth 20 Queue DEPTH True
     # chdev -l hdisk100 -a queue_depth=8 -P
     hdisk100 changed
     # lsattr -El hdisk100 -a queue_depth
     queue_depth 8 Queue DEPTH True
    
    But what qdepth does the kernel actually use? The only way to get the kernel's value is to use the kernel debugger:
     # echo scsidisk hdisk100 | kdb | grep queue_depth
       ushort queue_depth   = 0x14;
    
    What we see is the hex value of the qdepth. Use the below command to convert the value to decimal as it would be displayed by lsattr:
     # printf "%d\n" 0x14
     20
    

    12. How can I increase a LUN on the fly?

    Whenever the SAN admins increase a LUN I run cfgmgr, but my volume group does not recognize the new size. What to do?
    Just run
     # chvg -g 
    
    and the additional size can be used. Doesn't work for the rootvg and HACMP though¹.

    ¹ Note: According to IBM Tech Note IZ80021 these restrictions have been removed from the command as of AIX 6.1 TL04.

    13. How can I set the number of logical partitions to be synchronized in parallel?

    In normal operation the syncvg and varyonvg commands don't synchronize logical partitons in parallel resulting in a very long synchronization time. But this behaviour can be changed by setting the NUM_PARALLEL_LPS variable prior to run the synchronization commands:
    # export NUM_PARALLEL_LPS=8
    # varyonvg myvg
    
    or
    # export NUM_PARALLEL_LPS=8
    # syncvg -v myvg
    
    This way 8 logical partitions will be synchronized in parallel. Depending on available CPU resources this can speed up the synchronization nearly by a factor 8.
    With the syncvg command the same effect can be realized with the -P flag:
    # syncvg -P 8 -v myvg
    
    However, if you prefer to run varyonvg to synchronize logical partition mirrors setting the NUM_PARALLEL_LPS  variable is your only option.

    14. How can I get rid of "ghost paths"?

    It happens that a LUN is connected via two paths, but lspath  shows boths paths twice - once as Missing and another time as Enabled:
    # lspath -l hdisk151
    Missing hdisk151 fscsi0
    Missing hdisk151 fscsi1
    Enabled hdisk151 fscsi0
    Enabled hdisk151 fscsi1
    
    The reason usually is located somewhere in the SAN infrastructure - a new switchport, a replugged cable, etc. Anyway, how can I get rid of these "ghost paths" without affecting the good paths?
    Not a big deal - every path to a LUN has its unique path ID:
    # lspath -l hdisk151 -F "path_id:parent:path_status:status"  
    0:fscsi0:Missing:N/A
    1:fscsi1:Missing:N/A
    2:fscsi0:Available:Enabled
    3:fscsi1:Available:Enabled
    
    So all we have to do is to remove the two paths with the IDs 0 and 1...
    # rmpath -dl hdisk152 -i 0
    paths Deleted
    # rmpath -dl hdisk151 -i 1                             
    paths Deleted
    
    ...and the "ghost paths" are gone:
    # lspath -l hdisk151 -F "path_id:parent:path_status:status"
    2:fscsi0:Available:Enabled
    3:fscsi1:Available:Enabled
    
    # lspath -l hdisk151
    Enabled hdisk151 fscsi0
    Enabled hdisk151 fscsi1
    

    15. How do I create a mapfile to create an exact copy of a Logical Volume?

    Let's say hdisk100 is the disk holding the first and only copy of a LV called mylv.map and you want to create a second copy on hdisk101. The below command will do the trick:
    # lslv -m mylv | awk '/hdisk/ { printf( "hdisk101:%d\n", $2 ) }' | tee mylv.map
    hdisk101:1
    hdisk101:2
    hdisk101:3
    hdisk101:4
    
    If your LV is spread over multiple disks sed is your friend:
    # lslv -m mylv | awk '/hdisk/ { printf( "%s:%d\n", $3, $2 ) }' | sed -e 's/hdisk100\:/hdisk200\:/' -e 's/hdisk101\:/hdisk201\:/' | tee mylv.map
    hdisk200:1
    hdisk201:1
    hdisk200:2
    hdisk201:2
    hdisk200:3
    hdisk201:3
    hdisk200:4
    hdisk201:4 
    
    In the above example hdisk100 is to going to be copied to hdisk200 and hdisk101 to hdisk201. To actually create the mirror run mklvcopy with the -m switch:
    # mklvcopy -m mylv.map mylv 2
    

    16. How can I change the status of a removed PV back to active?

    After an I/O failure to a PV due to a down path or a system crash, a volume group may have a disk in a removed state:
    # lsvg -p rootvg
    rootvg
    PV_NAME PV STATE TOTAL PPs FREE PPs FREE DISTRIBUTION
    hdisk1  removed  432       136      76..00..00..00..60
    hdisk2  active   432       136      76..00..00..00..60
    
    We can use chpv to change the status of the PV back to active:
    # chpv -va hdisk1
    # syncvg -P 4 -v rootvg
    
    The switch '-P 4' to syncvg may be used to speed up the synchronization process by syncing 4 PPs in parallel.

    Miscellaneous

    1. How do I create users with long login names (more than 8 characters) under AIX 5.3?

    Since AIX version 5.3 one can create users with login names longer than 8 characters. In order to create such a login name you first have to enable longer login names. This can be done with:
    # chdev -l sys0 -a max_logname=13
    
    The above example allows login names with up to 12 characters.

    2. Can I use passwords with more than 8 (significant) characters?

    AIX always accepts passwords with more than 8 characters. But in fact only the first 8 characters are significant. If you want to use passwords with more characters the hash algorithm has to be changed in /etc/security/login.cfg:
     usw: 
      shells = /bin/sh,/bin/bsh,/bin/csh,/bin/ksh,/bin/tsh,/bin/ksh93,/usr/bin/sh,/usr/bin/bsh,/usr/bin/csh,/usr/bin/ksh,/usr/bin/tsh,/usr/bin/ksh93
      maxlogins = 32767 
      logintimeout = 60 
      maxroles = 8 
      auth_type = STD_AUTH 
      pwd_algorithm = ssha256
    
    The last line changes the hash algorithm from crypt  to ssha256. The algorithm allows passwords with up to 255 characters. Have a look to /etc/security/pwdalg.cfg  to see what other algorithms are allowed.

    3. What are the correct settings for daylight saving time in Central Europe?

    The timezone is set by the TZ environment variable. To set the timezone globally you have to change the TZ variable in /etc/environment. For the central eurpean countries (Brussels time) this variable should be set as follows:
     TZ=CET-1CST,M3.5.0/2:00,M10.5/3:00
    
    All services that read the timezone have to be restarted (e.g. cron). A reboot -of course- will restart everything.
    Please note that AIX's default time settings for Central Europe are not correct!
    Beginning with AIX 7.1 and AIX 6.1 TL5 symbolic ("Olson") values for TZ are also respected. For The Netherlands you could set:
     TZ=Europe/Amsterdam
    

    4. Can I identify deleted files still opened by a process?

    Just run fuser -V -d  on the filesystem you want to check for deleted but still opened files. This is an example for /tmp:
    # fuser -V -d /tmp
    /tmp:
    inode=7      size=56           fd=2      512238
    
    The PID points to the process which still has an open file descriptor to the deleted file:
    # ps -fp 512238
    USER         PID    PPID    C   STIME     TTY    TIME CMD
    root      512238       1    0   Mar 20      -    3:29 /usr/sbin/rsct/bin/ctcasd
    

    5. How can I figure out what values are known to device attributes?

    From the following example output we want to change the attribute init_link of a fibre channel adapter:
    # lsattr -El fcs0
    bus_intr_lvl  121        Bus interrupt level                                False
    bus_io_addr   0xbfc00    Bus I/O address                                    False
    bus_mem_addr  0xc0040000 Bus memory address                                 False
    init_link     al         INIT Link flags                                    True
    intr_priority 3          Interrupt priority                                 False
    lg_term_dma   0x800000   Long term DMA                                      True
    max_xfer_size 0x100000   Maximum Transfer Size                              True
    num_cmd_elems 200        Maximum number of COMMANDS to queue to the adapter True
    pref_alpa     0x1        Preferred AL_PA                                    True
    sw_fc_class   2          FC Class for Fabric                                True
    
    True in the last column indicates that we indeed can change the value of this attribute¹. But what is a valid value? This can be easily figured out with the lsattr command:
    # lsattr -Rl fcs0 -a init_link
    al
    pt2pt
    
    Valid values are al and pt2pt. And that's how we could change it:
    # chdev -l fcs0 -a init_link=pt2pt
    fcs0 changed
    

    ¹ Note: This example is taken from an AIX 7.1 box. With AIX 5.3 and 6.1 you would see 'False' here.

    6. How can I mount an ISO image file?

    With AIX 6.1 TL4 or newer you can use loopmount:
    # ls -l *.iso
    -rw-r--r--    1 root     system     43974656 Jan 13 17:05 dvd_aix_profilemanager.iso
    # loopmount -i dvd_aix_profilemanager.iso -o "-V cdrfs -o ro" -m /mnt
    # df /mnt
    Filesystem    512-blocks      Free %Used    Iused %Iused Mounted on
    /dev/loop0         84812         0  100%    21203   100% /mnt
    

    7. How can I fix a broken /dev/ipldevice?

    I migrated the rootvg to a different disk. Now I get tons of errors when running any mirroring command. I know a reboot solves the problem. But can I fix it without a reboot?
    The problem is that /dev/ipldevice points to the device the system was booted from. When you removed this device from the rootvg /dev/ipldevice points to a non-existing device and you see error messages like these:
    # unmirrorvg rootvg hdisk2
    
    0516-1734 rmlvcopy: Warning, savebase failed.  Please manually run 'savebase' before rebooting.
    0516-1734 unmirrorvg: Warning, savebase failed.  Please manually run 'savebase' before rebooting.
    
    You can fix it by relinking /dev/ipldevice to the disk holding the BLV. If you have your rootvg mirrored choose the first one.
    # lslv -l hd5
    hd5:N/A
    PV                COPIES        IN BAND       DISTRIBUTION  
    hdisk16           001:000:000   0%            001:000:000:000:000 
    
    # cd /dev
    # ls -l ipldevice
    crw-------    2 root     system       17,  2 Nov 18 2010  ipldevice
    # rm -f ipldevice
    # ln rhdisk16 ipldevice
    # ls -l ipldevice rhdisk16     
    crw-------    2 root     system       17, 16 Jun 25 10:58 ipldevice
    crw-------    2 root     system       17, 16 Jun 25 10:58 rhdisk16
    
    # savebase
    
    Please note that a hardlink is required.

    8. How do I extend a dump device?

    «sysdumpdev -e» estimates the size of the dump:
    # sysdumpdev -e
    0453-041 Estimated dump size in bytes: 547146956
    
    and «sysdumpdev -e» shows the location of the dump device:
    # sysdumpdev -l
    primary              /dev/hd7
    secondary            /dev/sysdumpnull
    copy directory       /var/adm/ras
    forced copy flag     TRUE
    always allow dump    TRUE
    dump compression     ON
    
    In our case it's hd7. The size of the dump device is the size of the underlying LV:
    # lslv hd7 | egrep 'PP SIZE|LPs'                
    MAX LPs:            512                    PP SIZE:        256 megabyte(s)
    LPs:                2                      PPs:            2
    
    In our example we need a dump device of at least 547146956 bytes ( = 522 MB) what is a bit more than what we have (2 * 256 MB = 512 MB). So we need to increase our dump device by 1 LP:
    # extendlv hd7 1
    # lslv hd7 | egrep 'PP SIZE|LPs'                
    MAX LPs:            512                    PP SIZE:        256 megabyte(s)
    LPs:                3                      PPs:            3
  • No comments:

    Post a Comment