7.7.4.6 CREATE GRIDDISK

Purpose

The CREATE GRIDDISK command creates a grid disk object on a specified cell disk or creates one or more grid disks on each cell disk in the storage server. The command also assigns initial attributes to each new grid disk.

Syntax

CREATE GRIDDISK  
   { ALL [[ CAPACITYOPTIMIZED | PERFORMANCEOPTIMIZED ] FLASHDISK | HARDDISK ] PREFIX={[']gdisk_name_prefix[']|'gdisk_name_prefix1[,gdisk_name_prefix2]...'}
      [,multi_attribute_name={[']attribute_value[']|'attribute_value1[,attribute_value2]...'} ]...
   | gdisk_name CELLDISK=cell_disk_name }
   [,attribute_name=[']attribute_value[']]...

Usage Notes

  • If an individual grid disk name (gdisk_name) is specified, then the grid disk is created on the cell disk specified by the CELLDISK argument. You must ensure that the grid disk name is unique across all storage servers. If the disk name is not unique, then it might not be possible to add the grid disk to an Oracle ASM disk group.

  • The length of a grid disk name is limited to 30 characters.

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

    If you do not fully specify the flash media type, ALL FLASHDISK is equivalent to ALL CAPACITYOPTIMIZED FLASHDISK on Extreme Flash (EF) storage servers containing capacity-optimized flash devices. On all other storage servers, ALL FLASHDISK is equivalent to ALL PERFORMANCEOPTIMIZED FLASHDISK.

  • If the ALL option is specified with a media type qualifier (FLASHDISK or HARDDISK), the command only creates grid disks on cell disks associated with the specified media type.

    Starting with Oracle Exadata System Software release 24.1.0, if you specify the ALL option without a media type qualifier (FLASHDISK or HARDDISK), then the command creates grid disks on the cell disks associated with the primary storage media on the storage server. This behavior ensures that grid disks created using the ALL option use the same media type, making it much less likely that you can mistakenly attempt to configure an Oracle ASM disk group or Exascale storage pool with a mixture of storage media. Specifically:

    • On Extreme Flash (EF) storage servers containing capacity-optimized flash devices, ALL with no media type qualifier is equivalent to ALL CAPACITYOPTIMIZED FLASHDISK.

    • On Extreme Flash (EF) storage servers containing only performance-optimized flash devices, ALL with no media type qualifier is equivalent to ALL PERFORMANCEOPTIMIZED FLASHDISK.

    • On all storage servers containing hard disk drives (HDDs), ALL with no media type qualifier is equivalent to ALL HARDDISK.

    Before Oracle Exadata System Software release 24.1.0, if the ALL option is specified without a media type qualifier, the command creates grid disks on all available cell disks regardless of media type.

  • The PREFIX option must be specified when ALL is used.

    The PREFIX option specifies one or more comma-separated prefix strings. Each prefix is used to create a grid disk on the underlying cell disk. The generated grid disk names are composed of the grid disk prefix followed by an underscore (_) and then the cell disk name.

    For example, CREATE GRIDDISK ALL PREFIX=data01 creates one grid disk on each available cell disk. In this case, if the cell disks are named CD_01_cell01, CD_02_cell01, CD_03_cell01, and so on, then the corresponding grid disk names are data01_CD_01_cell01, data01_CD_02_cell01, data01_CD_03_cell01, and so on.

    Use prefixes that match the Oracle ASM disk groups or Exascale storage pools that consume the grid disks. This helps you to identify where the grid disks are being used. Also, use short prefix values to ensure that the generated grid disk names stay within the 30-character limit.

  • multi_attribute_name specifies one of the following attributes, which may accept a comma-separated list of values:

    • size

    • offset

    • virtualSize

    • comment

    • storagePool

    If the command specifies multiple comma-separated PREFIX values, then for each multi_attribute_name you must specify only one value or the same number of values as in the prefix list. If one value is specified, it applies to all values in the prefix list. Otherwise, each entry in the list of attribute values applies to the corresponding value in the prefix list.

    For example, CREATE GRIDDISK ALL PREFIX='data01,data02', size='500G,300G' creates two grid disks on each available cell disk. In this case, size=500G is associated with PREFIX=data01, and size=300G is associated with PREFIX=data02.

    All other attribute settings require only one value at all times.

  • The size attribute determines the amount of storage space that is allocated to the grid disk. If the size attribute is not specified, then the grid disk consumes all of the available space on the cell disk.

    Grid disk space is allocated in 16 MB units, referred to as allocation units. If the size attribute is specified, then the allocated size is the largest multiple of allocation units that is less than or equal to the specified size. For example, if 300M is specified for the size attribute, then 288 MB (16x18) is allocated, because 288 is the largest multiple of 16 that is less than or equal to 300.

    A minimum of 1 allocation unit is always allocated, so the minimum size for a grid disk is 16 MB. Any size value less than 16 MB is rounded up to 16 MB.

    Before specifying the size attribute, ensure that you first determine the available free space on each target cell disk by using the LIST CELLDISK command. For example, LIST CELLDISK cdisk ATTRIBUTES freespace.

  • The offset attribute determines the position on the hard disk where the grid disk is allocated. The outermost tracks have lowest offset values. If the offset attribute is not specified, then the lowest available offset is automatically chosen in order of grid disk creation.

    Note:

    The offset attribute does not apply to flash storage.

  • The size and offset attributes are specified as a number of bytes, unless the suffix M (megabytes), G (gigabytes), or T (terabytes) is included with the number, such as size=300M, or size=150G.

  • The CREATE GRIDDISK ALL ... command skips disks which do not have enough free space for a minimum sized grid disk (16 MB). In this case, the skipped grid disks are identified in the command output and the command continues.

  • The value of the availableTo attribute is set to the names of the clients registered for DB-scoped security. The value for each client name is the database unique name (DB_UNIQUE_NAME). The specified clients are those that are allowed to access the grid disk. If a value is entered for availableTo, then only the specified clients have access to the grid disk; otherwise, any client can access the grid disk.

  • Do not edit the value of idp.type or idp.boundary. Oracle Exadata System Software passes a hint to Oracle ASM about the type of interleaved grid disk, either normal redundancy or high redundancy. Oracle ASM sets the default value for idp.type to static and idp.boundary to the type of redundancy used in the underlying grid disks. The default value of the idp.type attribute is static for Oracle Exadata Storage Server disk groups created on interleaved grid disks.

    Note:

    Interleaved grid disks are deprecated in Oracle Exadata System Software release 19.1.0.

  • The cachingPolicy attribute can be set to default or none. The default option allows the data in the grid disk to be cached in the flash cache. Flash cache is not used for data stored on grid disks with cachingPolicy=none.

  • The virtualSize attribute is used to create grid disks used in an Oracle ASM SPARSE disk group. The maximum virtual size for a sparse grid disk is approximately 100 TB. Sparse grid disks are available for Oracle Exadata Database Machine X3-2 and later.

    Note:

    The Oracle Database and Oracle Grid Infrastructure software must be release 12.1.0.2.0 BP5 or later when using sparse grid disks.

  • The storagepool attribute is used to create an Exascale pool disk, which is an Exascale-specific grid disk designated for use in an Exascale storage pool. The value of the storagepool attribute is the name of the Exascale storage pool that consumes the pool disk.

    When you specify the storagepool attribute, the resulting grid disks are marked as Exascale pool disks, and the storage pool name is written into the pool disk metadata.

    The CREATE GRIDDISK command does not immediately add the pool disks to the specified storage pool. The pool disks are only available for data storage after they are included in the storage pool, either during storage pool creation or after reconfiguring an existing storage pool.

Example 7-83 Creating Grid Disks

This examples shows how to create grid disks.

CellCLI> CREATE GRIDDISK ALL HARDDISK PREFIX='data01,data02', size='500G,300G'

CellCLI> CREATE GRIDDISK ALL HARDDISK PREFIX=data03

CellCLI> CREATE GRIDDISK data1_CD_01_cell01 CELLDISK=CD_01_cell01, size=200G

CellCLI> CREATE GRIDDISK data2_CD_02_cell01 CELLDISK=CD_02_cell01, size=200G

CellCLI> CREATE GRIDDISK data3_CD_03_cell01 CELLDISK=CD_03_cell01

CellCLI> CREATE GRIDDISK ALL PREFIX=data10, availableTo='+asm,db1,db2'

CellCLI> CREATE GRIDDISK hr7_CD_07_cell01 CELLDISK=CD_07_cell01, availableTo='asm_hr,hrdb0'

CellCLI> CREATE GRIDDISK GD123 CELLDISK=RECO_CD123, size=100G, cachingPolicy=none

Example 7-84 Creating a SPARSE Grid Disk

CellCLI> CREATE GRIDDISK spar01 celldisk=CD_01_cel01, size=10G, virtualsize=100G

Example 7-85 Creating Exascale Pool Disks 

CellCLI> CREATE GRIDDISK ALL HARDDISK prefix=pool1, storagepool=POOL1

Parent topic: CREATE