The first Utility Pricing Solution that HP delivered was CPU Instant Capacity. This provides the ability to acquire a system with extra CPU capacity for future upgrades. The CPUs are physically present in the system but are inactive so they don't participate in process scheduling by the operating system.
This section focuses primarily on the permanent activation of Instant Capacity CPUs. We will cover temporary activation in the next section.
CPU Instant Capacity Use Model
The use model for Instant Capacity is really quite simple. The goal of Instant Capacity is allow you to defer the cost of an upgrade you know you will need in the future. This upgrade could be needed because:
As part of the acquisition process for the server, you will work with your HP Sales technical consultant or authorized partner to ensure that there is sufficient spare capacity on the system to meet the needs of expected upgrades. The norm in the past was to pay the full cost of these resources from the beginning. Using Instant Capacity in this environment is an improvement because:
One thing to note is that the CPUs can be activated while the system is on line. To take advantage of this you will need to ensure that the extra CPUs are physically located in the nPars where they will be activated. Once you have determined how many Instant Capacity CPUs you want, you purchase what is called a right-to-access (RTA) license for the CPUs. When you need to upgrade the system, you simply send a purchase order to HP for the balance of the cost of those CPUs. HP will respond with information about how to access the Utility Pricing portal to get a right-to-use (RTU) codeword that can be used to license the additional CPUs. Once you have applied the codeword to any HP-UX partition in the system, you can then use the icod_modify command to activate processors in the relevant partition.
CPU Instant Capacity Requirements
The Instant Capacity program is a combination of a financial services agreement and the technology to implement it. The general principles of the program include the following:
Some other benefits of the Instant Capacity program include:
Using Instant Capacity CPUs to Do Processor Load-Balancing between nPars
An interesting feature of Instant Capacity is that the number of inactive CPUs is measured across the entire complex in a cell-based server. In other words, if you have a complex that has been split up into multiple hard partitions, it doesn't matter which partition the inactive CPUs are in. This is easier to explain using an example. Figure 8-4 shows a server complex with four cells, split into two nPartitions with two cells each and a total of four inactive Instant Capacity processors.
Figure 8-4. A Cell-Based Server with Two nPartitions and Instant Capacity Processors
In this picture you see that the system has been partitioned into two electrically isolated nPartitions. Each partition has two cells with a total of eight physical CPUs. However, there are two inactive CPUs in each partition, so these are really six CPU partitions, with a total of twelve active CPUs in the complex.
One other very important feature here is that these Instant Capacity CPUs can be activated and deactivated without requiring a reboot of any of the partitions. So if the workload in partition nPar1 experiences a spike in load, you can deactivate CPUs in nPar2 and activate the other two CPUs that are already physically present in nPar1. This is depicted in Figure 8-5.
Figure 8-5. Using Instant Capacity Processors to Increase CPU Capacity in nPar1
As you can see in this picture, there are still twelve active processors on the system. However, we now have eight active CPUs in nPar1 and only four active CPUs in nPar2. This makes it possible to satisfy the spike in load on the workloads running in nPar1 and the extra CPUs do not sit idle in nPar1 when they are not needed.
Of course, this can go the other way also. Suppose the workload in nPar1 is no longer busy and the workload in nPar2 experiences a spike. Figure 8-6 shows nPar2 with eight active CPUs.
Figure 8-6. Using Instant Capacity Processors to Increase CPU Capacity in nPar2
This makes it possible to satisfy the performance requirements in nPar2 with the same number of active CPUs on the system.
If you think about this, Instant Capacity allows you to:
If you are purchasing a cell-based system and plan to do consolidation by carving the system up into multiple nPartitions, you really should consider purchasing the system with some Instant Capacity resources so you can get this flexibility. This effectively makes it possible to share the spare capacity between the partitions rather than having it sit idle in one partition when it could be used in another. If you are considering getting permanent licenses for all the CPUs, this will reduce the cost of the system and give you additional flexibility for allocating resources to the workloads that need them.
Several important considerations:
The key to this last point is that you should ensure that each of the nPars has enough physical CPUs in the partition to satisfy the maximum amount of capacity that might be required for the workloads running there. Of course, if you guess wrong, you can always reconfigure your nPartitions to add additional cells to the partition, but this will require a reboot, so it is preferable to have some extra capacity there in the form of Instant Capacity CPUs.
Using Instant Capacity CPUs to Do Processor Load-Balancing between Separate Servers
A new capability provided on top of Instant Capacity is the ability to migrate the licenses between systems. This is effectively the same type of functionality as described above, but you now have the ability to do this across physically separate systems. This provides an additional capability to ensure that you don't have idle processors on one system when there are workloads on another that can use them. A few key points about this new capability:
Although there is an additional cost for this capability, this will probably be more than offset by the savings you will realize because you won't have to purchase permanent licenses for capacity that is only needed for short periods of time.