1Z0-078 practice question 8 of 15

Which two statements are true about Oracle Clustered ASM performance? (Choose two.)

Answer options

A: Data files, redo logs, and RMAN backup pieces must be stored in different ASM disk groups for optimal performance.

B: All ASM Disks belonging to a disk group should be of the same size for optimal performance. Correct answer

C: Hardware-based mirroring combined with ASM mirroring guarantees optimal performance.

D: All ASM Disks belonging to a disk group should have the same hardware specifications and storage attributes for optimal performance. Correct answer

E: To improve performance a database must have two disk groups; one for data and one for the fast recovery area.

Correct Answer:

B. All ASM Disks belonging to a disk group should be of the same size for optimal performance.; D. All ASM Disks belonging to a disk group should have the same hardware specifications and storage attributes for optimal performance.

Explanation

ASM stripes and mirrors files evenly across all disks in a disk group. Using disks of uniform size, rotational speed, interface, and latency ensures even I/O distribution and prevents the slowest or largest disks from becoming bottlenecks. Oracle best-practice documentation therefore recommends putting disks of identical capacity, performance characteristics, and storage attributes (sector size, redundancy capabilities) in the same ASM disk group for optimum throughput and balanced load.

Why Incorrect

A. Files of different types can reside in the same disk group; separation is optional, not a performance requirement.
C. Double mirroring (hardware + ASM) may add write overhead; it does not inherently “guarantee” better performance.
E. Having two disk groups for data and FRA is a design choice, not a prerequisite for performance.

References

1. Oracle Automatic Storage Management 19c Administrator’s Guide, Sec. 13.2 “ASM Best Practices”, bullet “Use disks that have similar performance and size” (PDF p. 13-4).

2. Oracle Database Storage Administrator’s Guide 19c, Sec. 2.6.2 “Striping and Mirroring Considerations” (PDF p. 2-12).

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