Neeraj Bhatia's Blog

October 7, 2011

Capacity Planning and Performance Management on IBM PowerVM Virtualized Environment

Filed under: Capacity - General,Virtualization — neerajbhatia @ 22:48

It’s always a great opportunity when you get a situation which you never faced, scenario you never worked on, technology you never experienced. As someone rightly said – the new challenges we confront today, decide our knowledge curve tomorrow. I believe in this philosophy and always challenge myself with something new.

As a capacity planner, I have to be proficient in virtualization techniques and latest happening in this space. Last year I got an opportunity to work on IBM’s power systems.  Being from Solaris/Linux background it was quite difficult in the beginning to grasp the terminologies as they are different from Oracle VM, Solaris logical domains. So I decided to learn it and get comfortable with it. My paper is a result of my efforts in that direction.

Virtualization is integral part of today’s Infrastructure and beleive it or not most of the applications/services we use on a daily basis run on virtualized environment “beautifully” wrapped with cloud’s charasteristics. There are several virtualization technologies and the vendor market is also crowded enough. In my paper I have discussed operating system virtualization offer from IBM. Hope you will enjoy the reading. Any comments (postive/negative), feedback, corrections are most welcome.

Link to the paper

Happy reading …

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2 Comments »

  1. Dear Neeraj,

    I read your article “Capacity Planning and Performance Management on IBM PowerVM Virtualized Environment” since I’m planning to implement shared pools on a 770. One thing is unclear to me about the Max Pool Capacity. Is it so that the sum of all capacity for the LPARs in this pool whether obtained through Level-0 and/or Level-1 can never exceed the Max Pool CPUs?

    Example: I have a pool with 2 uncapped LPARs, per lpar 0.5 Entitled CPU, 2 Virtual CPU. The pool has 3 CPUs max. Assumed that both LPARs at some point want to consume 1.8 CPU each, can these LPARs then max get 3 CPU and not the requested 3.6?

    Many thanks,
    Rob

    Comment by RobJKamphuis — January 12, 2012 @ 00:42 | Reply

  2. Hi Rob,

    Yes, you are right. The Maximum Pool Capacity defines an upper limit up to which the underlying partitions can consume the processor capacity. The micro-partitions in a shared-processor pool can’t get additional capacity even if there is spare capacity available in other shared-processor pools if its maximum capacity is exhausted (Page 16).

    In your example, since the maximum poor capacity is 3, both partitions in total can get maximum 3.0 processing units (and not 3.6) ,subject to the availability of the processing capacity.

    Just to elaborate further that why we need mutiple shared-processor pools at the first place. The reason is – because you want to prioritize a set of partitions to get more processing capacity without compromising with the number of active partitions (you can prioritize using entitled capacity but it would restrict number of partitions you can start at a time) and at the same time have the flexibity to support the spikes in utilization (using uncapped partitions and high value of their shared-processor pool’s maximum pool capacity). In the absence of multiple-shared processor pool you have to leverage entitled capacity and uncapped weight but that way all the uncapped partitions would compete for free CPU cycles and not just your set of “favourite” partitions. In multiple-shared processor pool you define a set of partitions and want to first distribute the available cycles first among them before donating it to public partitions.

    It is important to note that default shared-processor pool’s maximum pool capacity is always equals to active physical processors.

    I hope it helps!

    Cheers, Neeraj

    Comment by neerajbhatia — January 12, 2012 @ 08:09 | Reply


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