Oracle 参数 ASM_POWER_LIMIT 官方解释,作用,如何配置最优化建议
本站中文解释
参数
ASM_POWER_LIMIT参数是Oracle Automatic Storage Management(ASM )中的一个初始化参数,它表示ASM实例中对I/O访问组控制的最大功率值。前面的一个参数ASM_DISKGROUPS表示磁盘组(Disk Group)的名称,而Power Limit参数表示所有相关磁盘组共同最大可以消费的I/O功耗。
通常情况下,ASM_POWER_LIMIT参数建议设置成默认值7,除非有其他特殊需求,否则无需修改。正确的设置方法是:在实例正确启动的时,以sysdba权限连接SQL*Plus,然后运行命令:
alter system set asm_power_limit=7 Scope=SPFILE;
之后需要重启数据库,以使此更改生效。
官方英文解释
ASM_POWER_LIMIT
specifies the maximum power on an Oracle ASM instance for disk rebalancing.
Property | Description |
---|---|
Parameter type |
Integer |
Default value |
|
Modifiable |
|
Modifiable in a PDB |
No |
Range of values |
|
Basic |
No |
Oracle RAC |
Multiple instances can have different values. |
Footnote 1
Beginning with Oracle Database 11g Release 2 (11.2.0.2), if the COMPATIBLE
.ASM
disk group attribute is set to 11.2.0.2 or higher, then the range of values is 0 to 1024.
Note:
-
This parameter may only be specified in an Oracle Automatic Storage Management (Oracle ASM) instance.
-
In an Oracle Exadata or Oracle Data Appliance environment, you cannot set this parameter to 0.
The higher the limit, the faster rebalancing will complete. Lower values will take longer, but consume fewer processing and I/O resources.
If the POWER
clause of a rebalance operation is not specified, then the default power will be the value of ASM_POWER_LIMIT
.
See Also:
Oracle Automatic Storage
Management Administrator’s Guide for more information about using this parameter