ALTER DISKGROUP中的rebalance,ADD TEMPLATE子句等

文档地址：http://docs.oracle.com/cd/B19306_01/server.102/b14200/statements_1006.htm#i2168800

 

rebalance_diskgroup_clause ::=

 

rebalance_diskgroup_clause

 

    Use this clause to manually rebalance the disk group. AutomaticStorage Management redistributes datafiles evenly across alldrives. This clause is rarely necessary, because Automatic StorageManagement allocates files evenly and automatically rebalancesdiskgroups when the storage configuration changes. However, it isuseful if you want to use thePOWER clause to controlthe speed of what would otherwise be an automatic rebalanceoperation.

   POWERIn the POWERclause, specify a value from 0 to 11, where 0 stops the rebalanceoperation and 11 permits Automatic Storage Management to executethe rebalance as fast as possible. The value you specifyin thePOWER clause defaults to the value of theASM_POWER_LIMIT initialization parameter.

    If youomit the POWER clause, then Automatic StorageManagement executes both automatic and specified rebalanceoperations at the power determined by the value of theASM_POWER_LIMIT initialization parameter.

WAIT |NOWAIT Use this clause to specify when in the course of therebalance operation control should be returned to the user.

• Specify WAIT to allow a script that adds or removesdisks to wait for the disk group to be rebalanced before returningcontrol to the user. You can explicitly terminate a rebalanceoperation running inWAIT mode, although doing so doesnot undo any completed disk add or drop operation in the samestatement.

• Specify NOWAIT if you want control returned to theuser immediately after the statement is issued. This is thedefault.

You can monitor the progress of the rebalance operation byquerying the V$ASM_OPERATION dynamic performance view.

 

 

diskgroup_template_clauses::=

ADDTEMPLATE Use this clause to add one or more namedtemplates to a disk group. To determine the names of existingtemplates, query theV$ASM_TEMPLATE dynamic performance view.

ALTERTEMPLATE Use this clause to modify the attributesof a system default or user-defined disk group template. Only thespecified attributes are altered. Unspecified properties retaintheir current values.

template_name Specifythe name of the template to be added or modified. Template namesare subject to the same naming conventions and restrictions asdatabase schema objects. Please refer to"Schema Object Naming Rules" for information on database objectnames.

RedundancyLevel Specify the redundancy level of the newly added ormodified template:

• UNPROTECTED: Files to which this template areapplied are not protected by Automated Storage Management frommedia failures. Disks taken offline, either through system actionor by user command, can cause loss of unprotected files.UNPROTECTED is the only valid setting for externalredundancy disk groups. UNPROTECTED may not bespecified for templates in high redundancy disk groups. Oraclediscourages the use of unprotected files in high and normalredundancy disk groups.

• MIRROR: Files to which this template areapplied are protected by mirroring their data blocks. In normalredundancy disk groups, each primary extent has one mirror extent(2-way mirroring). For high redundancy disk groups, each primaryextent has two mirror extents (3-way mirroring). You cannot specifyMIRROR for templates in external redundancy diskgroups.

DiskStriping Specify how the files to which this template areapplied will be striped:

• FINE: Files to which this template areapplied are striped every 128KB.

• COARSE: Files to which this template are appliedare striped every 1MB.
  
  
  地址：http://docs.oracle.com/cd/B19306_01/server.102/b14231/storeman.htm#sthref1774
  Adding Templates to a Disk Group
  

     To add a new template for adisk group, you use the ADD TEMPLATE clause of theALTER DISKGROUP statement. You specify the name ofthe template, its redundancy attribute, and its stripingattribute.

  
  Note:

•    If the name of your new template is not one of the nameslisted inTable 12-5, it is not used as adefault template for database file types. To use it(即是自定义的模板，yournew template), you must reference its name when creating afile.