IVM & HMC difference

With IVM, dual VIO server configuration is not possible
- system power-on must be done by physically pushing the system power-on
button or remotely accessing ASMI
- Multiple systems can be managed via one HMC interface, but IVM can mange
only one system
- In Power5 some Power6 systems, you cannot assign physical adapters to
partitions by IVM
- Only one virtual SCSI adapter is supported for IVM-managed LPARs
- Multiple Shared Processor Pools are not supported on IVM-managed POWER6
systems

regards,
Guru

unable to find the boot device

While creating the bosboot or while listing the boot list we will get an error as "unable to find the boot device" or there will be no output while giving the command "bootinfo -b".
This is due to bugs on the OS(5.3 TL7 or 6.1 TL3/5 SP3) , please proceed the below steps.

Verify the /dev/ipldevice & /dev/ipl_blv
Verify the df -g (check for hd5)
use the command "ipl_varyon -i" command to verify the boot disk info
" You can able to see the rootvg's hdisk status as 'YES' "
if the ipldevice or ipl_blv is not there create the link as shown below
Link the rootvg's hdisk to ipldevice " ln /dev/rdsik# /dev/ipldevice"
Link the hd5 to ipl_blv "ln /dev/hd5 /dev/ipl_blv"
Now if everything looks good reboot the LPAR. It will resolve the issue

Note:-
Before doing any installation (TL upgrade, patching or OS migration) reboot the machine to be in the safer side.

Regards,
Guru