asm 11g r1_bestpractices_7_301

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  • 1.Oracle Database 11g Release 1 and 10g Release 2 Automatic Storage Management Overview and Technical Best Practices 7/30/09 1

2. Table of ContentsIntroduction ........................................................................................................................ 3Overview of Oracle Database 10g Release 2 ASM New Features .................................................. 4Overview of Oracle Database 11gR1 ASM New Features ............................................................ 4Scalability and Performance ................................................................................................... 4ASM installation .......................................................................................................... 6ASM SGA and parameter sizing ............................................................................................. 7ASM and privileges ...................................................................................................... 8ASMLIB ............................................................................................................................ 9Disks ............................................................................................................................... 10ASM and Multipathing ............................................................................................... 11DiskGroups ...................................................................................................................... 12Diskgroups and databases ............................................................................................ 14ASM redundancy and Failure Groups .................................................................................... 15New Space related columns in Oracle Database 10g Release 2 ............................................ 16Database Instances ............................................................................................................. 18Database consolidation and clustering ............................................................................ 1811gR1 ASM and Rolling Upgrade ................................................................................. 19ASM Database Multi-Version Support ........................................................................ 20Database processes to support ASM .............................................................................. 20Database Init.ora parameters to support ASM .................................................................. 21ASM and database shutdown dependencies ..................................................................... 21ASM and database deployment Best Practices ................................................................. 22Storage Management and Allocation...................................................................................... 22Rebalance and Redistribution ............................................................................................... 23Files and Aliases ................................................................................................................ 25Enhanced management for ASM ........................................................................................... 27ASM Command Line Interface (ASMCMD) ................................................................... 27DBMS_FILE_TRANSFER Utility Enhancements ............................................................ 29XML ASM Virtual Folder ........................................................................................... 29ASM Virtual Folder access via FTP ........................................................................... 30Templates ......................................................................................................................... 30Simplified ASM migration using EM ..................................................................................... 30ASM Management ............................................................................................................. 31Conclusion ....................................................................................................................... 33Appendix A. Views and Discover Strings ............................................................................... 34Appendix B. Migrating individual non-ASM datafiles to ASM ................................................... 35Appendix C. Creating extra controlfiles in ASM ...................................................................... 36Appendix D. ASM SQL scripts............................................................................................. 372 3. IntroductionIn Oracle Database 10g Release 2, storage management and provisioning for the database has been greatlysimplified using Automatic Storage Management (ASM). ASM provides filesystem and volume managercapabilities built into the Oracle database kernel. With this capability, ASM simplifies storage managementtasks, such as creating/laying out databases and diskspace management. Since ASM allows diskmanagement to be done using familiar create/alter/drop SQL statements, DBAs do not need to learn a newskill set or make crucial decisions on provisioning. An Enterprise Manager interface as well as a newcommand line utility (new in Oracle Database 10g Release 2) is also available for those ASMadministrators who are not familiar with SQL.ASM is a management tool specifically built to simplify the job of the DBA. It provides a simple storagemanagement interface across all server and storage platforms. ASM provides the DBA flexibility tomanage a dynamic database environment with increased efficiency. This feature is a key component ofGrid Computing and Database Storage Consolidation.The following are some key benefits of ASM:o I/O is spread evenly across all available disk drives to prevent hot spots and maximizeperformance.o ASM eliminates the need for over provisioning and maximizes storage resource utilizationfacilitating database consolidation.o Inherent large file support.o Performs automatic online redistribution after the incremental addition or removal of storagecapacity.o Maintains redundant copies of data to provide high availability, or leverage 3rd party RAIDfunctionality.o Supports Oracle Database 10g as well as Oracle Real Application Clusters (RAC).o Capable of leveraging 3rd party multipathing technologies.o For simplicity and easier migration to ASM, an Oracle Database 10g Release 2 database cancontain ASM and non-ASM files. Any new files can be created as ASM files whilst existing filescan also be migrated to ASM.o RMAN commands enable non-ASM managed files to be relocated to an ASM disk group.o Oracle Database 10g Enterprise Manager can be used to manage ASM disk and file managementactivities.o ASM reduces Oracle Database 10g cost and complexity without compromising performance oravailability. 3 4. This document will discuss the essentials of ASM, and cover the steps to discover disks, create a diskgroup,and eventually create a database within an ASM diskgroup, discussing some best practices along the way.The following components of ASM will be discussed:o Instances ASM instance and database instanceo ASM Diskso Diskgroupso Failure Groupso Rebalancing Capabilitieso ASM Files, Templates and Aliaseso ASM and Cluster Synchronization Services (CSS)Overview of Oracle Database 10g Release 2 ASM New FeaturesAutomatic Storage Management in Oracle Database 10g Release 2 expands the capabilities of ASM andprovides features and enhancements in the following categories:oDatabase consolidation and clustering o Database storage consolidation with Single Instance and RAC o Multiple database version support o Independent ASM Oracle homeoEasy database migration to ASM o Enterprise Manger (EM) ASM migration utilityoManagement flexibility and simplicity o Command Line Interface (CLI) o ASM file system view through XMLDB virtual folders o Enhanced ASM manageability and alerts o Enhancements in DBMS_FILE_TRANSFER utilityThis paper will introduce the new features of Automatic Storage Management (ASM) in Oracle Database10g Release 2, and describe the benefits and improvements in simplification and automation for managingOracle database files.See the following document for a high level overview of all the new Oracle Database 10g Release 2 ASMFeatures: ASM 10gR2 New Features http://asm.us.oracle.com/pdf/ASM R2 New Features.pdfOverview of Oracle Database 11gR1 ASM New FeaturesThe following are key features of 11gR1 ASM:Scalability and Performance Fast Mirror Resynchronization for ASM redundancy disks groups Preferred Read for ASM redundancy disks groups Support for large allocation units Optimized rebalance operationsRolling upgrade and patching supportNew security features Separate connect privilege, SYSASM, different from SYSDBAThe following is a link to the 11gR1 New Feature paper on OTN 11gR1 ASM New Features4 5. ASM InstancesIn Oracle Database 10g there are two types of instances: database and ASM instances. The ASM instance,which is generally named +ASM1, is started with the INSTANCE_TYPE=ASM init.ora parameter. Thisparameter, when set, signals the Oracle initialization routine to start an ASM instance and not a standarddatabase instance. Unlike the standard database instance, the ASM instance contains no physical files; suchas logfiles, controlfiles or datafiles, and only requires a few init.ora parameters for startup.Upon startup, an ASM instance will spawn all the basic background processes, plus some new ones that arespecific to the operation of ASM. The STARTUP clauses for ASM instances are similar to those fordatabase instances. For example, RESTRICT prevents database instances from connecting to this ASMinstance. NOMOUNT starts up an ASM instance without mounting any disk group. MOUNT optionsimply mounts all defined diskgroups2.The illus