Which two statements are true about ASM default templates?
A.
Default data file templates are only created by ASM when a normal redundancy disk group is created.
B.
Default template settings for redundancy depends on the disk group redundancy.
C.
Default templates for a disk group can be modified.
D.
Default template setting for striping depends on disk group redundancy.
E.
Templates may be shared across disk groups.
I think B and C are correct.
A. It is wrong, this independ on disk redundancy like external, hormal or high.
B. This is correct:
Templates are used to set attributes of files created in an Oracle ASM disk group.
When a file is created, redundancy and striping attributes are set for that file based on
an explicitly named template or the system template that is the default template for
the file type.
When a disk group is created, Oracle ASM creates a set of default templates for that
disk group. The set consists of one template for each file type (data file, control file,
redo log file, and so on) that is supported by Oracle ASM. For example, a template
named ONLINELOG provides the default file redundancy and striping attributes for all
redo log files written to Oracle ASM disks. Default template settings depend on the
disk group type. The default template for data files for a normal redundancy disk
group sets two-way mirroring, while the corresponding default template in a high
redundancy disk group sets three-way mirroring. You can modify these default
templates.
C. This is correct! See the last line above.
D. This is wrong! This depends on the file type first of all, but, this can be changed!
Templates are used to set attributes of files created in an Oracle ASM disk group. When a file is created, redundancy and striping attributes are set for that file based on an explicitly named template or the system template that is the default template for the file type.
See: “Oracle ASM system default templates attribute settings”
https://docs.oracle.com/cd/E11882_01/server.112/e18951/asmfiles.htm#OSTMG94230
E. This is not true! Every disk group has your set of templates
Thanks WGCM.
B is correct
When a disk group is created, Oracle ASM creates a set of default templates for that
disk group. The set consists of one template for each file type (data file, control file,
redo log file, and so on) that is supported by Oracle ASM. For example, a template
named ONLINELOG provides the default file redundancy and striping attributes for all
redo log files written to Oracle ASM disks. Default template settings depend on the
disk group type. The default template for data files for a normal redundancy disk
group sets two-way mirroring, while the corresponding default template in a high
redundancy disk group sets three-way mirroring.
C is correct
The default template for data files for a normal redundancy disk
group sets two-way mirroring, while the corresponding default template in a high
redundancy disk group sets three-way mirroring. You can modify these default
templates.
Yes, Great Explanation
More about the question “B”:
ASM uses coarse-grained striping to balance loads across all the disks in a disk group and fine-grained striping to reduce I/O latency. Coarse-grained stripes are always equal to the effective AU size. Effective AU size is the AU size defined by a disk group at creation. It can vary for each disk group. “”The fine-grained stripe size always equals 128 KB””. A fine-grained stripe is taken from within a series of coarse-grained stripes. Control files use fine-grained striping by default. All other file types use coarse-grained striping. This default striping method of coarse-grained or fine-grained can be changed with custom templates.
Ops! Question “D”
Correct B,C
D81242GC10 – Oracle Database 12c: ASM Administration 5-24