An LPAR can be activated with the command “lpar activate”:

lpar [-h <hmc>] [-m <ms>] [-p <profile>] activate [-b norm|dd|ds|of|sms] [-c] [-v] <lpar>
-h <hmc>     # Hardware Management Console
-m <ms>      # the Managed System of the LPAR
-p <profile> # the profile to use
-b norm      # normal bootmode
-b dd        # diagnostic with default bootlist
-b ds        # diagnostic with stored bootlist
-b of        # boot into OpenFirmware Mode
-b sms       # start SMS menu
-c           # open console for the LPAR
-v           # verbose only, show commands but don't execute

If an LPAR is powered off (“Not Activated” state), it can be activated with the “lpar activate” command:

$ lpar activate aix02
$

The last valid configuration (profile last*valid*configuration) is then used for the LPAR and a normal boot is carried out. This means an attempt is made to boot the installed operating system. If the LPAR has never been activated, e.g. because it was newly created, you will receive the following error message when you try to activate the LPAR:

$ lpar activate lpar15
hmc01: chsysstate -m ms01 -r lpar -o on -n lpar15
ERROR: remote HMC command returned an error (1)
StdErr: HSCL3680 Partition lpar15 cannot be activated due to insufficient resources in its current configuration.  Please activate the partition with a profile.
$

When activating an LPAR for the first time, a profile must be specified. The profile describes the configuration of the LPAR, such as number of processors, memory size, etc. Which profiles an LPAR has, can be displayed with the command “lpar lsprof”:

$ lpar lsprof lpar15
NAME      MEM_MODE  MEM   PROC_MODE  PROCS  PROC_COMPAT
standard  ded       1024  shared     1      default
$

Note: If the LPAR has already been activated, a profile with the name last*valid*configuration will be displayed.

If an LPAR has been created with the LPAR-Tool, the name standard is used for the profile by default. An LPAR can easily have multiple profiles with different configurations. When activating an LPAR, the desired profile can be specified with the “-p” (profile) option:

$ lpar -p standard activate lpar15
$

Sometimes you don’t want to boot the operating system when activating an LPAR. Therefore, the desired boot mode can be specified using the “-b” (boot mode) option. Often a system only needs to be booted into SMS mode; this can be done with “-b sms”:

$ lpar activate -b sms lpar15
$

Note: Of course, a desired profile can also be specified here with the “-p” option.

Since it is relatively common that a console is required after activating an LPAR, a console can be requested using the additional option “-c” (console):

$ lpar -p standard activate -b sms -c lpar15

Open in progress 

 Open Completed. 
…
PowerPC Firmware
Version AL740_167
SMS 1.7 (c) Copyright IBM Corp. 2000,2008 All rights reserved.
-------------------------------------------------------------------------------
Main Menu
1. Select Language
2. Setup Remote IPL (Initial Program Load)
3. Change SCSI Settings
4. Select Console
5. Select Boot Options
...
-------------------------------------------------------------------------------
Navigation Keys:
                                             X = eXit System Management Services
-------------------------------------------------------------------------------
Type menu item number and press Enter or select Navigation key:

The “-c” option starts the console in exactly the same way as the “lpar console” command!