Storage Administration - Oracle Exadata Recipes: A Problem-Solution Approach - page 279

cm01cel02: GridDisk SRECO_CD_02_cm01cel02 successfully created
... output omitted
cm01cel03: GridDisk SRECO_CD_00_cm01cel03 successfully created
cm01cel03: GridDisk SRECO_CD_01_cm01cel03 successfully created
cm01cel03: GridDisk SRECO_CD_02_cm01cel03 successfully created
... output omitted
[oracle@cm01dbm01 ~]$

6. When complete, rebuild an Oracle ASM disk group on these newly created Exadata grid

disks:

SQL> create diskgroup SRECO_CM01
normal redundancy
disk 'o/*/SRECO*'
attribute 'compatible.rdbms' = '11.2.0.3.0',
'compatible.asm' = '11.2.0.3.0',
'cell.smart_scan_capable' = 'TRUE',
'au_size' = '4M';

Diskgroup created.

SQL>

■ please see recipe 9-2 to learn more about appropriate settings for your au_size and other exadata-related
aSm disk group attributes.

Note

How It Works
Exadata grid disks are the building blocks for Oracle ASM disks on Exadata. Oracle uses ASM for its database storage
on Exadata. ASM disk groups consist of Exadata grid disks and grid disks are built on Exadata cell disks. Exadata grid
disks represent the storage available for Oracle ASM disks. When you create ASM disk groups, the devices you use are
grid disks, and grid disks are the disks exposed and available to Oracle ASM.
Dropping and creating Exadata grid disks is accomplished using the CellCLI drop griddisk and create
griddisk commands, as demonstrated in the solution of this recipe.
Exadata DMAs should strive for equally sized, well-balanced grid disk configurations in order for an ASM
disk group to contain extents on as many physical disks in your storage grid as possible. Doing so enables Exadata
to maximize disk I/O bandwidth, I/Os per second, and ultimately ensure that you've got a well-balanced, high-
performing storage platform on Exadata.
Oracle makes this effort easy on Exadata with its wildcard-capable CREATE GRIDDISK and CREATE DISKGROUP
syntax. To create equally sized grid disks with the same prefix on each disk across all storage cells, you simply use the
create griddisk all harddisk prefix='[prefix]', size=[size] syntax. You can also create single grid disks on
a single storage cell disk using the more verbose syntax below:

CellCLI> create griddisk GDTEST celldisk=CD_08_cm01cel01, size=100M

cm01cel01: GridDisk GDTEST successfully created

CellCLI>