Oracle 参数 ASM_PREFERRED_READ_FAILURE_GROUPS 官方解释，作用，如何配置最优化建议
本站中文解释
ASM_PREFERRED_READ_FAILURE_GROUPS参数，指定数据负载首选失败磁盘组。默认情况下，ASM通过均衡地负载预分配给各磁盘组来读取数据。 ASM_PREFERRED_READ_FAILURE_GROUPS参数可确保在故障磁盘组之外的健康磁盘组不会处理负载。
设置ASM_PREFERRED_READ_FAILURE_GROUPS参数的正确方法：
1、确定故障磁盘组的唯一标识符，可使用V$ASM_DISKGROUP视图的NAME列。
2、运行ALTER SYSTEM设置该参数：
ALTER SYSTEM SET ASM_PREFERRED_READ_FAILURE_GROUPS=’FAILGROUP_1,FAILGROUP_2′ SCOPE=BOTH;
其中，FAILGROUP_1和FAILGROUP_2是两个故障磁盘组的唯一识别号。
3、如果要从负载中排除特定磁盘组，可以继续添加磁盘组标识符：
ALTER SYSTEM SET ASM_PREFERRED_READ_FAILURE_GROUPS=’FAILGROUP_1,FAILGROUP_2,FAILGROUP_N’ SCOPE=BOTH;
4、如果要将所有磁盘组从失败中回复，可以将ASM_PREFERRED_READ_FAILURE_GROUPS参数设置为空：
ALTER SYSTEM SET ASM_PREFERRED_READ_FAILURE_GROUPS=” SCOPE=BOTH;
官方英文解释
ASM_PREFERRED_READ_FAILURE_GROUPS specifies the failure groups that contain preferred read disks. Preferred disks are instance specific.
| Property | Description |
|---|---|
|
Parameter type |
String |
|
Syntax |
|
|
Default value |
NULL |
|
Modifiable |
|
|
Modifiable in a PDB |
No |
|
Basic |
No |
|
Oracle RAC |
The value is different on different nodes |
Note:
The ASM_PREFERRED_READ_FAILURE_GROUPS initialization parameter is deprecated in Oracle Database 12c Release 2 (12.2.0.1) and may be desupported in a future release. It is replaced by the PREFERRED_READ.ENABLED disk group attribute.
See Oracle Automatic Storage
Management Administrator’s Guide for more information about the PREFERRED_READ.ENABLED disk group attribute.
To reset the parameter value to null, issue the following statement, which updates the server parameter file (SP file), then reboot Oracle ASM so that the change takes effect:
alter system reset asm_preferred_read_failure_groups;See Also:
Oracle Automatic Storage
Management Administrator’s Guide for more information about this parameter
