3 Replies Latest reply: Apr 21, 2013 4:07 AM by Marc Fielding RSS

    Question regarding IORM resource allocation.

      Folks need help on this question related to IORM resource allocation.

      For example if I configure an category plan for IORM with the following allocation
      - mission critical (90% on level 1)
      - critical ( 80% on level 2)
      - Maintenance ( 50% on level 3)
      - Others ( 50% on level 3)

      If there are no uncomsumed IO requests from each of the category the allocation will goes like this
      - Mission critica gets 90% of the I/O allocated
      - Critical gets (100-90) * 80% = 8
      - Maintenance and other will get (50% of remaining (100-90-8)* 50% =2 i.e 1 each.

      In case of unconsumed I/O how does the allocation works for example,If the I/O requests for all categories are saturating the cell and
      if the mission critical request only 20% of the toltal I/O and critical requests 30% of the total I/O .

      Since the unconsumed I/O on level n get passed to n-1 level and so on, what would be the allocation in this case for the Maintenance and other category?

        • 1. Re: Question regarding IORM resource allocation.
          Marc Fielding
          Hello Sameer,

          In your example, maintenance and others have equal shares. That means that any available capacity that makes it to level 3 would be equally divided between the two, subject to there being demand from each.

          So if mission-critical requests 20% of I/O and critical requests 30% of total (or 37.5% of remaining), 50% of original I/O capacity is still available at level 3.


          • 2. Re: Question regarding IORM resource allocation.
            Hi Marc,

            Thanks for your response, as always it is helpful.

            I did't get how did you get to the 37.5% figure, additionally I want to know is what percent of the remaining I/O requests represent the maximum amount allocate for the Maintenance group? will it be 25% as per your response that 50% is available to these groups and since both have equal share?

            The 50% is the unconsumed I/O requests at level 1+level 2 , so what would be I/O priority for those unconsumed I/O when it get passed to the level 3 ( maintenance and other category)? I am specifically looking for I/O priority for the unconsumed I/O request which gets to level 3 category?

            • 3. Re: Question regarding IORM resource allocation.
              Marc Fielding
              Hi Sameer,

              If you have 80% of capacity remaining at level 2, 37.5% of the remaining capacity equals 30% of the total capacity (37.5% * 80% = 30%)

              In your example, the maintenance group will receive a maximum of 50% of what's remaining at level 3. So yes, if you have 50% remaining at level 3 and sufficient workload, maintenance will receive 25% of capacity.

              I don't know how you're defining "priority" but in an IORM context priorities usually translate to levels in the plan: the lower-numbered levels will get priority access to I/O capacity before higher-numbered levels do.