LPAR CPU Utilization - Aix

This is a discussion on LPAR CPU Utilization - Aix ; Situation: System Name Min Desired Max LPAR1 1 1.5 2.0 LPAR2 0.5 1.0 2.0 LPAR3 0.5 1.0 2.0 1) If the frame has 2 overall CPU , would itbe able to start all three lpars on boot ? starting with ...

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Thread: LPAR CPU Utilization

  1. LPAR CPU Utilization

    Situation:

    System Name Min Desired Max
    LPAR1 1 1.5 2.0
    LPAR2 0.5 1.0 2.0
    LPAR3 0.5 1.0 2.0

    1) If the frame has 2 overall CPU , would itbe able to start all three
    lpars on boot ? starting with the minimum CPU.

    2) If the frame has 3 CPU can it start the first two with Desired and
    thrid with minimum conf ?

    When the LPAR boots , does the checking process start with first
    chcking desired and if there is no desired available then it would
    start with the minimum ?

    Ciao

  2. Re: LPAR CPU Utilization


    "invincible" wrote in message
    news:4cf9ec23-57ec-4cbc-b569-c825e9756932@l64g2000hse.googlegroups.com...
    > Situation:
    >
    > System Name Min Desired Max
    > LPAR1 1 1.5 2.0
    > LPAR2 0.5 1.0 2.0
    > LPAR3 0.5 1.0 2.0
    >
    > 1) If the frame has 2 overall CPU , would itbe able to start all three
    > lpars on boot ? starting with the minimum CPU.
    >
    > 2) If the frame has 3 CPU can it start the first two with Desired and
    > thrid with minimum conf ?
    >
    > When the LPAR boots , does the checking process start with first
    > chcking desired and if there is no desired available then it would
    > start with the minimum ?
    >
    > Ciao


    Since nobody else has responded yet here is my guess based on my
    understanding of how it works:

    Case 1:
    On boot CPU will be allocated to LPARs based on the Desired amount, and then
    based on the Min amount, so LPAR1 would get 1.5, LPAR2 would get 0.5, and
    LPAR3 would not start. I'm not certain on the order that LPARs start but I
    think there is some weighting involved.

    Case 2:
    Yes. Same algorithm,. LPAR1 gets 1.5, LPAR2 gets 1. LPAR3 gets 0.5.

    This is my understanding from reading the documentation, we have the
    allocation set so all LPARs have desired set such that the sum is equal to
    the box capacity. Now I have no idea what happens if PLM kicks in soon
    after boot, but before all LPARs are started.






  3. Re: LPAR CPU Utilization

    On May 21, 9:27 pm, "Bruce" wrote:
    > "invincible" wrote in message
    >
    > news:4cf9ec23-57ec-4cbc-b569-c825e9756932@l64g2000hse.googlegroups.com...
    >
    >
    >
    > > Situation:

    >
    > > System Name Min Desired Max
    > > LPAR1 1 1.5 2.0
    > > LPAR2 0.5 1.0 2.0
    > > LPAR3 0.5 1.0 2.0

    >
    > > 1) If the frame has 2 overall CPU , would itbe able to start all three
    > > lpars on boot ? starting with the minimum CPU.

    >
    > > 2) If the frame has 3 CPU can it start the first two with Desired and
    > > thrid with minimum conf ?

    >
    > > When the LPAR boots , does the checking process start with first
    > > chcking desired and if there is no desired available then it would
    > > start with the minimum ?

    >
    > > Ciao

    >
    > Since nobody else has responded yet here is my guess based on my
    > understanding of how it works:
    >
    > Case 1:
    > On boot CPU will be allocated to LPARs based on the Desired amount, and then
    > based on the Min amount, so LPAR1 would get 1.5, LPAR2 would get 0.5, and
    > LPAR3 would not start. I'm not certain on the order that LPARs start but I
    > think there is some weighting involved.
    >
    > Case 2:
    > Yes. Same algorithm,. LPAR1 gets 1.5, LPAR2 gets 1. LPAR3 gets 0.5.
    >
    > This is my understanding from reading the documentation, we have the
    > allocation set so all LPARs have desired set such that the sum is equal to
    > the box capacity. Now I have no idea what happens if PLM kicks in soon
    > after boot, but before all LPARs are started.


    thankyou Bruce for the clarification

  4. Re: LPAR CPU Utilization

    On 21 mei, 13:51, invincible wrote:
    > Situation:
    >
    > System Name * * *Min * Desired * Max
    > LPAR1 * * * * * * * * 1 * * * * 1.5 * * * 2.0
    > LPAR2 * * * * * * * * 0.5 * * *1.0 * * * 2.0
    > LPAR3 * * * * * * * * 0.5 * * *1.0 * * * 2.0
    >
    > 1) If the frame has 2 overall CPU , would itbe able to start all three
    > lpars on boot ? starting with the minimum CPU.
    >
    > 2) If the frame has 3 CPU can it start the first two with Desired and
    > thrid with minimum conf ?
    >
    > When the LPAR boots , does the checking process start with first
    > chcking desired and if there is no desired available then it would
    > start with the minimum ?
    >
    > Ciao


    Th IBM redbook SG247039 "Partitioning Implementations
    for IBMEserver p5 Servers", chapter 3.4 Partition Load Manager is
    quite clear on this

  5. Re: LPAR CPU Utilization

    On May 21, 5:51*am, invincible wrote:
    > Situation:
    >
    > System Name * * *Min * Desired * Max
    > LPAR1 * * * * * * * * 1 * * * * 1.5 * * * 2.0
    > LPAR2 * * * * * * * * 0.5 * * *1.0 * * * 2.0
    > LPAR3 * * * * * * * * 0.5 * * *1.0 * * * 2.0
    >
    > 1) If the frame has 2 overall CPU , would itbe able to start all three
    > lpars on boot ? starting with the minimum CPU.
    >
    > 2) If the frame has 3 CPU can it start the first two with Desired and
    > thrid with minimum conf ?
    >
    > When the LPAR boots , does the checking process start with first
    > chcking desired and if there is no desired available then it would
    > start with the minimum ?
    >
    > Ciao


    My understanding (from class) is as follows:

    The minimum is the minimum amount of hardware you can take the LPAR
    down to, i.e. the minimum it needs to run. The desired amount is what
    it will attempt to allocate, the max is the maximum amount of
    resources it can be given. The LPARS start based on the Desired
    value. The only time the minimum becomes important is if you are
    dynamically deallocating hardware, the minimum sets a limit on what
    you can take. The maximum value does the same for what you can give
    the LPAR.

    Based on your example, (assuming you bring up your frames in numerical
    order) if your frame has 2 CPU's, LPAR1 would start, but the other two
    would not. If your frame had 3 CPU's LPAR1 would start, LPAR2 would
    start, LPAR3 would not. The weight value of your LPARs determines
    which LPAR has priority in grabbing available resources. How you
    weight your LPARs also changes how they will come up. If LPAR3 had
    the highest weight (the default is 128) then it would come up first
    regardless of the state of the other two, and it would also grab any
    free resources first to meet the Desired requirements to come up, if
    it was able.

    I strongly recommend reading the Redbook on it...and getting your
    hands on the HMC guide, which has a good overview of weighting and
    Desired vs Min vs Max.

    I hope this helps answer your question.

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