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Which two are true concerning the allocation of I/O resources by the IORM within the CELLSRV
process?

A.
If two consumer groups A and B in the PROD database get 10% and 15% respectively of
resource allocation, then the percentage of I/O resource would be the same if they got 20% and
30% respectively, provided that the category plans and inter database plans are unchanged, and
consumer groups A and B are still mapped to the same category.

B.
If two consumer groups C and D In the PROD database get 10% and 15% respectively of
resource allocation, then the percentage of I/O resource would be the same if they still got 10%
and 15% respectively and were remapped to a different category by the DBA, provided that the
category plans and Interdatabase plans are unchanged.

C.
If two consumer groups P and Q In the PROD database get 20% and 10% respectively of
resource allocation, then the percentage of I/O resource would be the same if they got 10% and
5% respectively, and the Interdatabase plan has changed, provided that the category plan is
unchanged, and consumer groups A and B are still mapped to the same categories.

D.
Log Writer I/O and Control File I/O are high priority I/O managed automatically by IORM.

E.
Database Writer I/O is considered to be the highest priority I/O and is managed based on
attributes of the IORM plan.

Explanation:
*(not A, Not B)Rules in an interdatabase resource plan specify allocations to
databases, not consumer groups.
*IORM Rules
IORM is only “engaged” when needed.
/ (D)Redo and control file writes always take precedence.
/ (Not E)DBWR(database writer)writes are scheduled at the same priority as user IO.
/IORM does not intervene if there is only one active consumer group on one database.
/Any disk allocation that is not fully utilized is made available to other workloads in relation to the
configured resource plans.
/Background IO is scheduled based on their priority relative to user IO.
/For each cell disk, each database accessing the cell has one IO queue per consumer group and
three background queues
Note:
*Use IORM metrics to track
/I/O load per Consumer Group (IOPS, MBPS, disk utilization %)
/I/O throttling per Consumer Group
Reference:Using IORM with Exadata

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