Oracle_052_lesson_p5

wxsheng

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 SQLPlus  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:>　　Copyright (c) 1982, 2009, Oracle.  All rights reserved.

　　Connected to an>　　SQL> startup
　　ASM instance started
　　Total System Global Area  284565504 bytes

　　Fixed>
　　Variable>　　ASM Cache                  25165824 bytes
　　ASM diskgroups mounted
　　ASM diskgroups volume enabled
　　SQL> shutdown abort
　　Starting and Stopping ASM Instances Using srvctl  用srvctl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
　　$ srvctl start asm -o mount
　　$ srvctl stop asm -f
　　$ srvctl status asm
　　ASM is running on edrsr25p1
　　Starting and Stopping ASM Instances Using asmcmd  用ASMCMD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
　　$ asmcmd

　　Connected to an>　　ASMCMD> startup
　　ASM instance started
　　Total System Global Area  284565504 bytes

　　Fixed>
　　Variable>　　ASM Cache                  25165824 bytes
　　ASM diskgroups mounted
　　ASM diskgroups volume enabled
　　ASMCMD> shutdown --abort
　　ASM instance shut down

　　Connected to an>

　　ASM disks are divided into allocation units (AU):

　　AU>
　　Default AU>　　Small enough to be cached by database and large enough for efficient sequential access

　　Allowable AU>　　1, 2, 4, 8, 16, 32, or 64 MB
　　Large AUs may be useful in very large database (VLDB) scenarios or when using specialized storage hardware
　　ASM files:
　　Are a collection of ASM extents composed of AUs

　　Variable>　　Appear as normal files to the database kernel
　　Have file names that start with '+'
　　For example, +DATA/orcl/datafile/system.256.689832921
　　May be associated with an optional alias file name
　　For example, +DATA/dbfiles/mydb/system01.dbf
　　Are evenly distributed across disks in a disk group
　　Are mirrored according to the policies defined in the disk group
　　Striping Granularity  条带化粒度
　　1、ASM separates striping for load balance and striping for latency:
　　Coarse-grain striping concatenates allocation units for load balancing.
　　数据文件粗粒度，以AU如1M为单元逐磁盘写入。
　　2、Fine-grain striping puts 128 KB stripe units across groups of allocation units to improve latency.
　　Disk group with 8 disks and external redundancy

　　Default AU>　　First 1 MB extent written as 128 KB stripes across 8 AUs
　　细粒度 ，以128K为单元逐磁盘写入，如控制文件、日志文件用细粒度。
　　管理ASM磁盘组
　　CREATE DISKGROUP
　　ALTER DISKGROUP
　　DROP DISKGROUP
　　Creating and Dropping Disk Groups Using SQLPlus
　　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

　　SQLPlus:>　　Copyright (c) 1982, 2009, Oracle.  All rights reserved.
　　..
　　SQL> CREATE DISKGROUP dgroupA NORMAL REDUNDANCY
　　FAILGROUP controller1 DISK

　　'/devices/A1' NAME diskA1>　　'/devices/A2',
　　FAILGROUP controller2 DISK
　　'/devices/B1',
　　'/devices/B2';
　　SQL> DROP DISKGROUP dgroupA INCLUDING CONTENTS;
　　例：
　　Remove a disk from dgroupA:
　　ALTER DISKGROUP dgroupA DROP DISK A5;
　　Add and drop a disk in a single command:  增加和删除DISK用1条命令完成
　　ALTER DISKGROUP dgroupA   DROP DISK A6
　　ADD FAILGROUP controller3        DISK '/dev/sdi1' NAME A9;
　　Add and drop a disk in a single command:
　　ALTER DISKGROUP dgroupA UNDROP DISKS;
　　例：
　　Adding Disks to Disk Groups
　　ALTER DISKGROUP dgroupA ADD DISK
　　'/dev/sde1' NAME A5,
　　'/dev/sdf1' NAME A6,
　　'/dev/sdg1' NAME A7,
　　'/dev/sdh1' NAME A8;
　　ALTER DISKGROUP dgroupA ADD DISK '/devices/A*';
　　ASMCMD> lsdsk
　　desc  v$asm_disk;
　　create  diskgroup  dg_test  external   redurancy  disk '/dev/sdi5'  name  i5;
　　ASMCMD>lsdg
　　drop  diskgroup  dg_test  including  contents;
　　ASM Disk Group Compatibility  ASM磁盘组兼容性

　　Retrieving ASM Metadata 检索ASM元数据
　　SQL> SELECT f.type, f.redundancy, f.striped, f.modification_date, a.system_created, a.name FROM v$asm_alias a, v$asm_file f WHERE a.file_number = f.file_number and a.group_number = f.group_number and type='DATAFILE';
　　TYPE      REDUND  STRIPE  MODIFICAT  S  NAME
　　DATAFILE  MIRROR  COARSE  08-JUL-09  Y  SYSTEM.256.689832921
　　DATAFILE  MIRROR  COARSE  08-JUL-09  Y  SYSAUX.257.689832923
　　..
　　ASMCMD> ls -l +DATA/orcl/datafile
　　Type      Redund  Striped  Time             Sys  Name
　　DATAFILE  MIRROR  COARSE   JUL 08 21:00:00  Y SYSTEM.256.689832921
　　DATAFILE  MIRROR  COARSE   JUL 08 21:00:00  Y SYSAUX.257.689832923
　　..