7.7.4.2 CREATE CELLDISK

Purpose

The CREATE CELLDISK command creates a cell disk object and assigns initial attributes to the object. You can use the ALL option to automatically create cell disks on multiple devices.

Syntax

CREATE CELLDISK  {  
   ALL [[ CAPACITYOPTIMIZED | PERFORMANCEOPTIMIZED ] FLASHDISK | HARDDISK ] 
  |cdisk1 attribute_name=value,[attribute_name=value]... [FORCE]
  |((name=cdisk2,attribute_name=value,[attribute_name=value]...)
  [,(name=cdisk3,attributename=value,[attributename=value]...)]...)
  }

Usage Notes

The attributes that can be specified during creation are the cell disk name (cdiskN), comment, lun, size, and physicalDisk.

• Either lun or physicalDisk is required when adding a specifically-named cell disk.

  • When a physical disk is provided, a single-disk LUN is created, and that LUN is used to create the cell disk. The LUN is flagged as automatically-created.

  • When a LUN is provided, that device is used to create the cell disk.

• You can use the size attribute when adding a new disk that is a different size than the existing disks. You must specify a value for size that is less than or equal to the maximum allowed cell disk size.

• CREATE CELLDISK ALL is a shortcut command to create all candidate cell disks for the cell. This operation occurs in two steps:

  • LUNs are configured for all physical disks that are not already configured. These LUNs are flagged as automatically-created LUNs.

  • All LUNs that are not configured as cell disks are used to create cell disks. These cell disks are initially named according to the template CD_lunname_cellname. This name can later be changed using the ALTER CELLDISK command.

    Note:

    LUNs with a second or third extended file system (ext2/ext3) are ignored during the CREATE CELLDISK ALL operation.

  • You can include size to create all cell disks with the specified size, instead of attempting to use the entire disk. If you do not specify size with the CREATE CELLDISK ALL command, then:

    • On disks without a partition containing the Exadata System Software, Management Server (MS) creates the cell disks with a size that is equal to the smallest physical disk size in the cell (which is also the maximum cell disk size allowed in the cell).
    • On disks containing a system partition, MS creates the cell disk with a size that is equal to the maximum allowed cell disk size minus the size of the system partition.

• The FLASHDISK option limits the CREATE CELLDISK command to cell disks that are flash disks.

  Starting with Oracle Exadata System Software release 24.1.0, you can optionally specify CAPACITYOPTIMIZED or PERFORMANCEOPTIMIZED before FLASHDISK to create cell disks only on the specified flash media type.

• The HARDDISK option limits the CREATE CELLDISK command to cell disks that are hard disks.
• The list form of CREATE CELLDISK enables you to add a series of cell disks in a single command.
• The FORCE keyword overrides the following error conditions:
  • The physical disk provided is already part of an existing LUN.
  • The LUN provided is already associated with a cell disk.

  FORCE causes the LUN to be reused to create the new cell disk. Any preexisting configuration is lost. FORCE is not an option for CREATE CELLDISK ALL or for the list form of CREATE CELLDISK.

• The INTERLEAVING option has been deprecated. Starting with Oracle Exadata System Software release 19.1.0, attempts to create interleaving grid disks will be automatically converted to normal grid disk creation. Interleaving grid disks created in earlier Oracle Exadata System Software releases will continue to operate normally.

Cell disks are created automatically using the CREATE CELLDISK ALL command. This command creates single-disk LUNs from all available physical disks, and then creates cell disks from all available LUNs.

When a cell disk is created, metadata describing the cell disk is written to the cell disk itself and to the cell configuration files. Approximately 48 MB of the cell disk is allocated for the cell disk metadata partition. On a subsequent restart, Cell Server (CELLSRV) attempts to rediscover the created cell disk by reading configuration data on the disk. Any hardware changes in the cell might cause a change in the LUN and device name for a cell disk. The rediscovery mechanism that runs during the cell restart process changes the cell disk configuration accordingly.

Example 7-79 Creating a Cell Disk

CellCLI> CREATE CELLDISK ALL

CellCLI> CREATE CELLDISK cdisk03 lun=0_3

CellCLI> CREATE CELLDISK cdisk04 physicalDisk='I2:1:2'
CellCLI> CREATE CELLDISK CD_08_cell06 lun=0_8, size=300M

CellCLI> CREATE CELLDISK CD_03_cell04 lun=0_3

CellCLI> CREATE CELLDISK CD_05_cell09 physicalDisk='2I:1:2'