Expert Oracle Exadata - Parent Directory

CHAPTER 14 STORAGE LAYOUTCellCLI> CREATE GRIDDISK ALL HARDDISK PREFIX=DATA_DG, size=744.6813GThese grid disks were used to create the following DATA_DG disk group. Notice how each grid diskwas created on a separate cell disk:SYS:+ASM2> select dg.name diskgroup,substr(d.name, 6,12) cell_disk,d.name grid_diskfrom v$asm_diskgroup dg,v$asm_disk dwhere dg.group_number = d.group_numberand dg.name ='DATA'and failgroup = 'CELL03'order by 1,2;DISKGROUP CELL_DISK GRID_DISK---------- ------------ ---------------------DATA_DG CD_00_CELL03 DATA_DG_CD_00_CELL03DATA_DG CD_01_CELL03 DATA_DG_CD_01_CELL03DATA_DG CD_02_CELL03 DATA_DG_CD_02_CELL03DATA_DG CD_03_CELL03 DATA_DG_CD_03_CELL03…DATA_DG CD_10_CELL03 DATA_DG_CD_10_CELL03DATA_DG CD_11_CELL03 DATA_DG_CD_11_CELL03Using interleaving in this example, DATA_DG_CD_00_CELL03 (the first grid disk) is allocated to the outermost tracks of the outer (fastest) region of the CD_00_CELL03 cell disk. The next grid disk,DATA_DG_CD_01_CELL03, is created on the outermost tracks of the slower, inner region of cell diskCD_01_CELL03. This pattern continues until all 12 grid disks are allocated. When the next set of grid disksis created for the RECO_DG disk group, they start with the inner region of cell disk 1 and alternate frominner to outer region until all 12 grid disks are created. Figure 14-7 shows how the interleaving policywould look if two grid disk groups were created.Cell Disk 1Cell Disk 2Second Disk Group(RECO_DG)Outer Region(faster)Cell Disk 3Inner Region(slower)First Disk Group(DATA_DG)Figure 14-7. The interleaving allocation policy476