Edit: I want my enterprise class server.
Originally posted June 7, 2016 on AIXchange
You likely know that we can run multiple operating systems on Power servers. With powerful POWER8 servers, we can consolidate workloads such as AIX, IBM i, and Linux and run them simultaneously on the same server — assuming it’s not one of the newer L or LC Linux-only models.
But about those L and LC boxes: They’ve come up a lot in my recent conversations with customers. While IBM is quick to remind customers that it’s still heavily invested in AIX and IBM i and they’re not going away, they’re also up front with their message about Linux and POWER8 servers: It’s a powerful combination.
When customers are interested in going head to head with x86 servers and competing on cost, the Linux-only L and LC models running PowerKVM virtualization make for an easy case. You’ll get better performance at a lower price. In addition, IBM has also made it convenient for new Power customers to run PowerKVM, in that you don’t need an HMC to manage your systems. Obviously an enterprise that doesn’t use the HMC may not want to invest the time to learn about HMCs and VIO servers.
It’s great to see the interest in these offerings. However, I often end up reminding my customers that an existing IBM solution, the PowerVM hypervisor, might actually be a better option for running their Linux workloads.
Linux workloads can run on smaller scale-out servers, but they can also run on larger systems. This is where PowerVM fits in. It handles Linux workloads, even if you’re not running AIX or IBM i on your frame.
PowerVM is a mature virtualization offering that’s been running mission-critical workloads for years. Think about it: When is the last time you have had an issue with PowerVM? In addition, when compared with PowerKVM, PowerVM has a better guaranteed quality of service and lower virtualization overhead (because the hypervisor is in the firmware rather than running QEMU). With the ability to have multiple VIO servers, you have higher availability for your systems, and the capability to perform maintenance on those redundant VIO servers. Because you have a smaller attack surface with a firmware-based hypervisor, there’s also better VM segregation and better security. In addition, PowerVM allows you to have shared processor pools to reduce licensing costs and guarantee a certain amount of resources to a group of workloads.
PowerVM offers other advantages. You can choose to set up your LPARs with shared dedicated processors. When defining LPARs, you can guarantee a minimum entitlement for your LPAR and you can hard-cap your virtual machines. Assuming you’re running on higher-end hardware, you’ll be able to use capacity on demand and dynamically change more of the settings on your LPARs compared to what you can do with PowerKVM.
As I said, it’s great that IBM has an option in PowerKVM that competes with x86 systems on cost and performance. But here’s the thing many customers forget: Replacing 20 x86 machines with 20 Power L or LC models isn’t the only option. You may find it more beneficial to consolidate those 20 x86 servers into a small number of beefier Power servers running PowerVM. Your data center cabling, power and cooling requirements will all go down, while your average server utilization will go up.
Sure, you could alternatively replace those 20 x86 machines with a smaller number of Linux-only machines. In doing so, you’ll get better performance per core with Power. But with larger enterprise servers, you can have a far greater number of cores and much more available memory to work with when compared to any of the scale-out models.
Even as IBM continues to update and advance its Linux story, there’s still much to be said for consolidating workloads through PowerVM. These servers remain well worth considering.