IBM PowerVM only is available on IBM POWER machines. It makes live much easier, compared to bare metal machines (OPAL) or machines with KVM. Personally I would not like to manage systems that don't have IBM PowerVM. The current line-up always includes IBM PowerVM (firmware built-in).
Each LPAR comes with a profile that sets a minimum, desired and maximum capacity (like for CPU). You can freely change the allocated CPU between the minimum and maximum on-the-fly. If you want to change the resource below the set minimum or above the set maximum, you need to shutdown the partition first and change the profile. It would be nice if there was a way to do that without downtime too.
(Setting the maximum very high is fine for CPU but not for memory as it allocates a fixed percentage of the maximum (not the current) size for internal housekeeping).
When you manage your Power system with an HMC, a lot of firmware updates can be done concurrent (on-the-fly), not requiring a power-cycle of the machine. If you use Novalink to manage your systems, this proces becomes broken and you need downtime on your physical system. You can use Live Partition Mobility to move every partition off of this system first, but still...
The product works. It provides the proven environment to support IBM's primary operating systems that run on the IBM Power processing systems. This by extension includes the IBM various storage products that work within that environment. It has proven to be seamless as the environment has grown and as various new products and version updates have been added. As with most IBM products, the support is excellent.
Since it is built into the firmware (hardware) it requires no separate installation (except for the Virtual I/O servers, if you need those). Both HMC and Novalink (with PowerVC) support IBM PowerVM well and offer a user-friendly interface to setting up LPARs and making changes, most on the fly. Modern systems also give insights into performance, power consumption etc. A lot of separate tools exist to show more details, like LPAR2RRD, IBM Instana, IBM Turbonomic etc.
IBM PowerVM is the best and most stable product in the virtualization market. It gives the best performance with IBM Power Server, especially its best solution, where we have to run critical applications and save applications licensing costs. It provides a lot of good features like LPM, shared processor pool...etc, which makes the environment more flexible.
It has provided the performance we need during month end and year end closing cycles.
It has been very reliable with little to no downtime.
We have been able to stretch our IT dollars because the refresh rate on IBM Power can run for years. Also, we have been able to add many more VMs to physical machines than other platforms can run.
