Oracle_052_lesson_p5

Posted 2020-12-30

Managing the ASM Instance管理ASM实例

you should be able to:
1、Describe the benefits of using ASM
2、Manage the ASM instance
3、Create and drop ASM disk groups
4、Extend ASM disk groups
5、Retrieve ASM metadata by using various utilities

ASM：内存+进程

sqlplus / as sysasm;
v$asm_disk;
v$asm_diskgroup;

shared pool：元数据信息
large pool ：大池，并行操作的
asm cache： 重平衡，（值最小1，最大11，越大重平衡越快）
free memory： 空闲内存

ASM实例初始化参数
The ASM instance uses a small subset of the parameters that an Oracle Database instance uses.

[INSTANCE_TYPE = ASM
ASM_POWER_LIMIT = 1
ASM_DISKSTRING = ‘/dev/sda1‘,‘/dev/sdb*‘
ASM_DISKGROUPS = DATA2, FRA
ASM_PREFERRED_READ_FAILURE_GROUPS = DATA.FailGroup2
DIAGNOSTIC_DEST = /u01/app/oracle
LARGE_POOL_SIZE = 12M
REMOTE_LOGIN_PASSWORDFILE = EXCLUSIVE]

SQL> show parameter spfile;
SQL>show parameter instance_type;

ASM Instance: Dynamic Performance Views ASM动态性能视图
ASM只有动态性能视图，文件是保存在OS的$ORACLE_HOME/dbs/orapw+asm中的

The ASM instance hosts memory-based metadata tables presented as dynamic performance views.
Accessed by ASM utilities to retrieve metadata-only information using the SQL language
Contains many dedicated ASM-related views such as:
V$ASM_ALIAS V$ASM_ATTRIBUTE V$ASM_CLIENT
V$ASM_DISK V$ASM_DISK_iosTAT V$ASM_DISK_STAT
V$ASM_DISKGROUP V$ASM_DISKGROUP_STAT V$ASM_FILE
V$ASM_OPERATION V$ASM_TEMPLATE

先关DB，再关ASM。先开ASM，再开DB；
Starting and Stopping ASM Instances Using SQL*Plus 用sqlplus起停ASM实例

$ . oraenv
ORACLE_SID = [orcl] ? +ASM
The Oracle base for ORACLE_HOME=/u01/app/oracle/product/11.2.0/grid is /u01/app/oracle
$ sqlplus / AS SYSASM
SQL*Plus: Release 11.2.0.1.0 - Production on Wed Jul 8 20:46:46 2009
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ASM instance started

Total System Global Area 284565504 bytes
Fixed Size 1336028 bytes
Variable Size 258063652 bytes
ASM Cache 25165824 bytes
ASM diskgroups mounted
ASM diskgroups volume enabled
SQL> shutdown abort