The IBM Hardware Management Console is a standalone linux based machine which provides a standard user interface for configuring and operating partitioned and SMP systems. The HMC supports the system with features that enable a system administrator to manage configuration and operation of partitions in a system, as well as to monitor the system for hardware problems. It consists of a 32-bit Intel-based desktop PC with a DVD-RAM drive.
Notes: Always consult your HMC manual. Use these commands as is, preferably in testing environment before production. They should work on many hmc/power versions. If there is some command limited to a version, it will be mentioned.

How to list the system connections. This way you can check what error you have if you are not able to see the partitions on a squadron.

hscroot@gzhmc$ lssysconn -r all

How to check if the lpars have connection with the current HMC. This is useful when you have issues related to DLPAR operations.

hscroot@gzhmc$ lspartition -dlpar

Example of working one:

<#36> Partition:<7*9117-MMA*56A3R4A, , 192.168.207.63>
       Active:<1>, OS:<AIX, 6.1, 6100-06-05-1115>, DCaps:<0x2c5f>, CmdCaps:<0x1b, 0x1b>, PinnedMem:<1137>

Example of non-working one:

<#37> Partition:<4*9117-MMA*56A5R9A, , 192.168.207.23>
       Active:<0>, OS:<, , >, DCaps:<0x0>, CmdCaps:<0x0, 0x0>, PinnedMem:<0>

What to do if you reconnect the management system to HMC and it is not recognized (to clear the HMC's connection history):

hscroot@gzhmc$ mksysconn -o auto

How to list 3 days of console events:

hscroot@gzhmc$ lssvcevents -t console -d 3

How to list 3 days of console events for a specific lpar:

hscroot@gzhmc$ lssvcevents -t console -m PARTITION -s ALL -d 3

How to list 3 days of hardware events:

hscroot@gzhmc$ lssvcevents -t hardware -d 3

How to list 3 days of hardware events for a specific lpar:

hscroot@gzhmc$ lssvcevents -t hardware -m PARTITION -s ALL -d 3

How to do HMC restart:

hscroot@gzhmc$ hmcshutdown -r -t0

How to list HMC version:

hscroot@gzhmc$ lshmc -V

How to list HMC hardware information, including the serial number:

hscroot@gzhmc$ lshmc -v

How to list managed systems (enter lssyscfg alone for more):

hscroot@gzhmc$ lssyscfg -r sys -F name

How to list lpars by name, id, state and current profile of LPARNAME:

hscroot@gzhmc$ lssyscfg -m FRAME -r lpar --filter "lpar_names=LPARNAME" -F name,lpar_id,state,curr_profile

How to list lpars by name, id, state and current profile in a managed system:

hscroot@gzhmc$ lssyscfg -m FRAME -r lpar -F name,lpar_id,state,curr_profile

How to list squadron's processors, real and virtual:

hscroot@gzhmc$ lshwres -r proc -m FRAME --level lpar -F lpar_name,curr_proc_units,curr_procs

How to list total processors of the squadron:

hscroot@gzhmc$ lshwres -r mem  -m FRAME --level sys -F configurable_sys_mem installed_sys_mem curr_avail_sys_mem sys_firmware_mem

How to list total memory of the squadron:

hscroot@gzhmc$ lshwres -r mem  -m FRAME --level sys -F configurable_sys_mem installed_sys_mem curr_avail_sys_mem sys_firmware_mem

How to list memory for each lpar in a squadron:

hscroot@gzhmc$ lshwres -r mem -m FRAME --level lpar -F lpar_name,curr_mem

How to display vios from all squadrons:

hscroot@gzhmc$ for FRAME in $(lssyscfg -r sys -F name); do printf "$FRAME\n";lssyscfg -r lpar -m $FRAME -F name,lpar_env|grep vio; done

How to search a partition name on all squadrons:

hscroot@gzhmc$ for FRAME in $(lssyscfg -r sys -F name); do printf "$FRAME:\n";lssyscfg -r lpar -m $FRAME -F name,lpar_env|grep PARTITION; done

How to soft reset a system running in FullPartitionMode (power4):

hscroot@hmc> chsysstate -n FRAME -r sys -o reset

How to hard reset a system running in FullPartitionMode (power4):

hscroot@hmc> chsysstate -n FRAME -r sys -o off

How to soft reset LPAR partition via HMC:

power4:

hscroot@gzhmc$ chsysstate -m FRAME -r lpar -n PARTITION -o reset

power5:

hscroot@gzhmc$ chsysstate -r lpar -m FRAME -o shutdown -n PARTITION

How to stop LPAR partition via HMC:

power4:

hscroot@gzhmc$ chsysstate -m pserver -r lpar -n mylpar -o off

power5:

hscroot@gzhmc$ chsysstate -m FRAME -r lpar -o shutdown -n PARTITION --immed

How to stop LPAR partition via HMC with dump:

hscroot@gzhmc$ chsysstate -m FRAME -r lpar -o dumprestart -n PARTITION

How to start LPAR partition via HMC (use "-b" option to start in different mode than normal, e.g. "sms" for sms menu):

hscroot@gzhmc$ chsysstate -r lpar -m FRAME -n PARTITION -f PROFILE -o on

How to connect to LPAR partition via HMC (via vtmenu or mkvterm):

1. vtmenu

2. select frame

3. select partition number

or:

hscroot@gzhmc$ mkvterm -m FRAME -p PARTITION

How to remove an existing terminal connection:

hscroot@gzhmc$ rmvterm -m FRAME -p PARTITION

How to connect to HMC via ssh tunneling:

1. Connect to gateway as usual but with the additional options highlighted in green: ssh gateway -L 3333:HMCIP:443 (where HMCIP = THE IP OF YOUR HMC)

2. Go to your favorite browser on your station and access the following address: https://localhost:3333

How to check the current disk space on HMC:

hscroot@gzhmc$ monhmc -r disk

How to remove all temporary HMC files from all file systems:

hscroot@gzhmc$ chhmcfs -o f -d 0

How to back up critical HMC data via command line interface:

To DVD:

hscroot@gzhmc$ bkconsdata -r dvd

Via NFS:

hscroot@gzhmc$ bkconsdata -r nfs -h NFSIP -l /hmc/backup/

How to back up partition profile data via command line interface:

hscroot@gzhmc$ bkprofdata -m FRAME -f dvd

How to check the date and time when the last critical console data backup was performed:

hscroot@gzhmc$ lssvcevents -t console -d 9999|grep 'backup of critical'

How to check the date and time when the last profile data backup was performed:

hscroot@gzhmc$ lssvcevents -t console -d 9999|grep 'Profile data'

How to make a new password policy in HMC with hscroot user:

Create it:

hscroot@gzhmc$ mkpwdpolicy –i	\
"name=gzadm,		\
description=,		\
min_pwage=1,		\ 
pwage=180,		\
min_length=4,		\
hist_size=10,		\
warn_pwage=7,		\
min_digits=0,		\
min_uppercase_chars=0,	\
min_lowercase_chars=0,	\
min_special_chars=0"

Activate it:

hscroot@gzhmc$ chpwdpolicy -o a -n gzadm

Change the password:

hscroot@gzhmc$ chhmcusr -u gzadm -t passwd

Disable the policy:

hscroot@gzhmc$ chpwdpolicy -o d

Remove the policy:

hscroot@gzhmc$ rmpwdpolicy -n gzadm

How to list user's settings:

NOTE: these values are all changeable via chhmcusr command.

ibm0htz1@frmpphmb40itdnm:~> lshmcusr --filter "names=hscroot"
name=hscroot,taskrole=hmcsuperadmin,description=HMC Super User,pwage=99999,resourcerole=ALL:,authentication_type=local,remote_webui_access=1,remote_ssh_access=1,min_pwage=0,session_timeout=0,verify_timeout=15,idle_timeout=0,inactivity_expiration=0,resources=<ResourceID = ALL:><UserDefinedName = AllSystemResources>,password_encryption=md5,disabled=0

What to do if you get the following error on DLPAR dynamic operations: HSCL297A There are some mismatches between pending and current values.

Assuming the memory was involved in this error, run the rsthwres command to re-sync the values.

hscroot@gzhmc$ rsthwres -r mem -m FRAME

How to free up partition resources with chhwres command in Power 7:

You have a currently active partition with 0.6 processing units assigned to it and you want to stop it and not using it for a while.

hscroot@gzhmc:~> lparls | grep PARTITION
   PARTITION             Running 
hscroot@gzhmc:~> lparlscpu | grep PARTITION
   PARTITION             0.5

You stop the partition, normally but the 0.6 processing unit remains allocated.

hscroot@gzhmc:~> lparls | grep PARTITION
   PARTITION             Not Activated
hscroot@gzhmc:~> lparlscpu | grep PARTITION
   PARTITION             0.6

Use the chhwres command to free up this resource from the partition:

hscroot@gzhmc:~> chhwres -r proc -m FRAME -o r --id 6 --procunits 0.6
hscroot@gzhmc:~> lparlscpu | grep PARTITION
   PARTITION

Also, the partiton's profile will not be modified:

hscroot@gzhmc:~> lparinfo PARTITION
PARTITION
  On frame FRAME
  Current State:  Not Activated
  OS version: AIX 6.1 6100-05-01-2410
 
  Profile properties:
  Profile properties:
name=Default,lpar_name=PARTITION,lpar_id=6,lpar_env=aixlinux,all_resources=0,
min_mem=512,desired_mem=20480,max_mem=34576,min_num_huge_pages=0,desired_num_huge_pages=0,
max_num_huge_pages=0,mem_mode=ded,hpt_ratio=1:64,proc_mode=shared,min_proc_units=0.1,
[color=green]desired_proc_units=0.6[/color],max_proc_units=2.0,min_procs=1,desired_procs=4,max_procs=8,
sharing_mode=uncap,uncap_weight=64,shared

If you change your mind and have to start the lpar back, it will re-acquire the 0.6 cores without any problems and without other modifications. END!

Inspiration:
http://www.unixwerk.eu/aix/hmc-howto.html