Which two statements are true about Oracle Clustered ASM performance? (Choose two.)
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 have the same hardware specifications and storage attributes for optimal performance.
C.
To improve performance a database must have two disk groups; one for data and one for the fast recovery area
D.
Hardware-based mirroring combined with ASM mirroring guarantees optimal performance
E.
All ASM Disks belonging to a disk group should be of the same size for optimal performance.
Correct B,E
Performance Characteristics When Grouping Disks
Oracle ASM load balances the file activity by uniformly distributing file extents across all of the disks in a disk group. For this technique to be effective it is important that disks in a disk group be of similar performance characteristics. For example, the newest and fastest disks might reside in a disk group reserved for the database work area, and slower drives could reside in a disk group reserved for the fast recovery area.
There might be situations where it is acceptable to temporarily have disks of different sizes and performance characteristics coexist in a disk group. This would be the case when migrating from an old set of disks to a new set of disks. The new disks would be added and the old disks dropped. As the old disks are dropped, their storage is migrated to the new disks while the disk group is online.
Source:
https://docs.oracle.com/database/121/OSTMG/GUID-BC6544D7-6D59-42B3-AE1F-4201D3459ADD.htm#OSTMG94136
D81242GC10 – Oracle Database 12c: ASM Administration 4-66
Correct: B
Correct: E
correct: B, E