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INTRODUCTION TO ORACLE Lynnwood Brown System Managers LLC Introduction to Oracle Automatic Storage Management (ASM) Copyright System Managers LLC 2008.

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Presentation on theme: "INTRODUCTION TO ORACLE Lynnwood Brown System Managers LLC Introduction to Oracle Automatic Storage Management (ASM) Copyright System Managers LLC 2008."— Presentation transcript:

1 INTRODUCTION TO ORACLE Lynnwood Brown System Managers LLC Introduction to Oracle Automatic Storage Management (ASM) Copyright System Managers LLC 2008 all rights reserved.

2 Introduction to ASM File system preparation: On the filer: Create Aggregate from multiple disks Create volume(s) on the Aggregate Create LUNs on the volumes (LUNs initiator groups maps WWPN/WWNN from the filer to the server. On the Unix/Linux server: Boot server to discover the new device Run mkfs to create the file system Create mount point Mount device on the mount point Copyright System Managers LLC 2008 all rights reserved.

3 Introduction to ASM Automatic Storage Management (ASM) Introduced in Oracle 10g, Automatic Storage Management (ASM) simplifies administration of Oracle related files by allowing the administrator to reference disk groups rather than individual disks and files, which are managed by ASM. In an ASM environment the regular Unix/Linux file system is replaced by the ASM file system. The mkfs utility is NOT run. ASM works with raw devices.

4 Introduction to ASM ASM Instance Creation Create instance initialization file init+ASM.ora in the /tmp directory. Contents of the file: INSTANCE_TYPE=ASM Connect to the ASM instance: –export ORACLE_SID=+ASM –sqlplus / as sysdba Create instance spfile: SQL> CREATE SPFILE FROM PFILE='/tmp/init+ASM.ora'; File created. Copyright System Managers LLC 2008 all rights reserved.

5 Introduction to ASM Start the ASM instance: SQL> startup nomount ASM instance started Total System Global Area bytes Fixed Size bytes Variable Size bytes Database Buffers 0 bytes Redo Buffers 0 bytes Copyright System Managers LLC 2008 all rights reserved.

6 Introduction to ASM ASM Startup Options FORCE - Performs a SHUTDOWN ABORT before restarting the ASM instance. MOUNT - Starts the ASM instance and mounts the disk groups specified by the ASM_DISKGROUPS parameter. NOMOUNT - Starts the ASM instance without mounting any disk groups. OPEN - This is not a valid option for an ASM instance. Copyright System Managers LLC 2008 all rights reserved.

7 Introduction to ASM ASM Shutdown Options NORMAL - The ASM instance waits for all connected ASM instances and SQL sessions to exit then shuts down. IMMEDIATE - The ASM instance waits for any SQL transactions to complete then shuts down. It doesn't wait for sessions to exit. TRANSACTIONAL - Same as IMMEDIATE. ABORT - The ASM instance shuts down instantly. Copyright System Managers LLC 2008 all rights reserved.

8 Introduction to ASM ASMCMD ASMCMD is a command-line utility that you can use to easily view and manipulate files and directories within Automatic Storage Management (ASM) disk groups. It can list the contents of disk groups, perform searches, create and remove directories and aliases, display space utilization Accessing the ASMCMD CLI Set ORACLE_HOME and ORACLE_SID to the ASM instance Type asmcmd at the OS command prompt ASMCMD > Copyright System Managers LLC 2008 all rights reserved.

9 Introduction to ASM Every file created in ASM gets a system-generated filename, otherwise known as a fully qualified filename. This is analogous to a complete path name in a local file system. An example of a fully qualified filename is : +dgroup2/sample/controlfile/Current ASM generates filenames according to the following scheme: +diskGroupName/databaseName/fileType/fileTypeTag. file.incarnation In the previous fully qualified filename, dgroup2 is the disk group name, sample is the database name, controlfile is the file type, and so on. Copyright System Managers LLC 2008 all rights reserved.

10 Introduction to ASM Using ASMCMD commands example ASMCMD [+] > cd +dgroup1 ASMCMD [+DGROUP1] > cd sample/datafile ASMCMD [+DGROUP1/SAMPLE/DATAFILE] > ls EXAMPLE SYSAUX SYSTEM UNDOTBS UNDOTBS USERS ASMCMD [+DGROUP1/SAMPLE/DATAFILE] > rm undotbs Copyright System Managers LLC 2008 all rights reserved.

11 ASMCMD Commands Copyright System Managers LLC 2008 all rights reserved. CommandFunction lsList directory cdChange directory mkdirMake directory rmRemove ASM file lsctList client information helpDisplay help screen exitExit ASMCMD

12 Introduction to ASM Creating ASM Disk Groups Disk groups are created using the CREATE DISKGROUP statement. This statement allows you to specify the level of redundancy: NORMAL REDUNDANCY - Two-way mirroring, requiring two failure groups. HIGH REDUNDANCY - Three-way mirroring, requiring three failure groups. EXTERNAL REDUNDANCY - No mirroring for disks that are already protected using hardware mirroring or RAID.

13 Introduction to ASM Creating ASM Disk Groups SQL > CREATE DISKGROUP disk_group_1 NORMAL REDUNDANCY FAILGROUP failure_group_1 DISK '/devices/diska1' NAME diska1, '/devices/diska2' NAME diska2, FAILGROUP failure_group_2 DISK '/devices/diskb1' NAME diskb1, '/devices/diskb2' NAME diskb2; Disk Group Created Dropping/deleting ASM Disk Groups SQL > DROP DISKGROUP disk_group_1 INCLUDING CONTENTS; Disk Group Dropped Copyright System Managers LLC 2008 all rights reserved.

14 Introduction to ASM Add disks to a DISKGROUP SQL > ALTER DISKGROUP disk_group_1 ADD DISK '/devices/disk*3', '/devices/disk*4'; Note: The wildcard "*" can be used to reference disks so long as the resulting string does not match a disk already used by an existing disk group. Drop disks from a DISKGROUP SQL > ALTER DISKGROUP disk_group_1 DROP DISK diska2; Copyright System Managers LLC 2008 all rights reserved.

15 Introduction to ASM Disks can be resized using the RESIZE clause of the ALTER DISKGROUP statement. The statement can be used to resize individual disks, all disks in a failure group or all disks in the disk group. If the SIZE clause is omitted the disks are resized to the size of the disk returned by the OS. Resize a specific disk. SQL > ALTER DISKGROUP disk_group_1 RESIZE DISK diska1 SIZE 100G; Resize all disks in a failure group. SQL > ALTER DISKGROUP disk_group_1 RESIZE DISKS IN FAILGROUP failure_group_1 SIZE 100G; Resize all disks in a disk group. SQL > ALTER DISKGROUP disk_group_1 RESIZE ALL SIZE 100G;

16 Introduction to ASM Creating a tablespace in an ASM environment: SQL> CREATE TABLESPACE NEW_TS DATAFILE '+disk_group_1' SIZE 100M AUTOEXTEND ON; Tablespace Created Copyright System Managers LLC 2008 all rights reserved.

17 ASM Views View NameASM InstanceDB Instance V$ASM_ALIASDisplays a row for each alias present in every disk group mounted by the ASM instance. Returns no rows V$ASM_CLIENTDisplays a row for each database instance using a disk group managed by the ASM instance. Displays a row for the ASM instance if the database has open ASM files. V$ASM_DISKDisplays a row for each disk discovered by the ASM instance, including disks which are not part of any disk group. Displays a row for each disk in disk groups in use by the database instance. The ASM configuration can be viewed using the V$ASM_% views:

18 ASM Views View NameASM InstanceDB Instance V$ASM_DISKGROUPDisplays a row for each disk group discovered by the ASM instance. Displays a row for each disk group mounted by the local ASM instance. V$ASM_FILEDisplays a row for each file for each disk group mounted by the ASM instance. Displays no rows. V$ASM_OPERATIONDisplays a row for each file for each long running operation executing in the ASM instance. Displays no rows.

19 ASM File Names Filename TypeFormat Fully Qualified ASM Filename+dgroup/dbname/file_type/file_type_ta g.file.incarnation Numeric ASM Filename+dgroup.file.incarnation Alias ASM Filenames+dgroup/directory/filename There are several ways to reference ASM file. Some forms are used during creation and some for referencing ASM files. The forms for file creation are incomplete, relying on ASM to create the fully qualified name, which can be retrieved from the supporting views. The forms of the ASM filenames are summarized below.

20 Introduction to ASM ASM provides the following functionality: Manages groups of disks, called disk groups. Manages disk redundancy within a disk group. Provides near-optimal I/O balancing without any manual tuning. Enables management of database objects without specifying mount points and filenames. Supports large files. Copyright System Managers LLC 2008 all rights reserved.


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