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?
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.
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?
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.