Database Upgrade/Migration Options & Tips Sreekanth Chintala Database Technology Strategist

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  • Database Upgrade/Migration Options & Tips Sreekanth Chintala Database Technology Strategist
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  • Global Marketing 2Confidential Agenda Very high level overview of Migration/Upgrade options No technical details
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  • Global Marketing 3Confidential About the Speaker 3 West Virginia University (M.S) Supporter of UT Longhorns 11+ Yrs of Oracle, 17+ years in IT RACSIG Web chair (2008-2010) Presenter at OIUG, OOW, Local user groups Technical Editor Sreekanthchintala@gmail.com Sreekanth_chintala@dell.com
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  • Global Marketing 4Confidential Database Upgrade Moving DB from one version to another on the same server It is NOT: Upgrading the Server Upgrading the OS Upgrading the Storage
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  • Global Marketing 5Confidential Database Upgrade 10gR1 11gR2
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  • Global Marketing 6Confidential Database Migrations Move to another Server Move to another Data Center Move to another (later) Version Migrations are typically done as part of End-of- Life refresh, usually followed by Database Upgrade
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  • Global Marketing 7Confidential Database Upgrade Methods Database Upgrade Assistant GUI Uses GUI to upgrade The DBUA performs pre-upgrade checks Manual Upgrade Performed via SQL-Plus Commands Use pre-upgrade script to validate Modify Cluster Registry entries for RAC Databases.profile changes, environment variables Tips Use GUI method, especially for RAC Databases Take a backup before the upgrade Check news groups to be aware of any known issues
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  • Global Marketing 8Confidential Factors Source & Target DB Version Acceptable Downtime Size of the database Source & target Operating Systems
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  • Global Marketing 9Confidential Concerns Downtime Performance Data Field Conversions Upgrade Issues Fallback / Backout Training
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  • Global Marketing 10Confidential Database Migration Options Complete Downtime Export and Import using Data Pump (or exp/imp) CTAS Backup & Restore Transportable Tablespaces Minimal Downtime Logical/Physical Standby EMC SRDF Copy ASM Rebalance Near Zero Downtime Oracle Streams Golden Gate
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  • Global Marketing 11Confidential Export / Import Database needs to be down or open read only Take an export on the source system Copy the export dump to destination system Import into the database Advantages Simple to use, proven track record Works well for smaller DB sizes (say < 50GB) Gotchas Size of the database dictates the amount of downtime needed Import time is 3-4 times longer than export time Older Unix system may have 2G file size limitations.
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  • Global Marketing 12Confidential Export / Import 10gR1 11gR2 Export Copy Export Copy Tips Use NFS mount that can be accessed from both source and destination Data Pump provides many features Review the nature of data. Bring over the static tables, partitions ahead of time, reduce the total downtime In case of RAC instances, leverage all instances to import different tables Indexes can be re-built on the destination. No need to import them Collect stats after the import Beware of security and password changes
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  • Global Marketing 13Confidential SQL Plus-CTAS Database needs to be down or open read only Copy the Tables via DB Link Gotchas Size of the database and the network throughput dictates the amount of downtime needed Dont use it on Live tables Advantages No intermediate storage needed Operations can be performed in parallel for non-related tables
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  • Global Marketing 14Confidential CTAS 10gR1 11gR2 Tips Review the nature of data. Bring over the static tables, partitions ahead of time, reduce the total downtime In case of RAC instances, leverage all instances to import different tables Indexes can be re-built on the destination. No need to import them Collect stats after the import DB Link
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  • Global Marketing 15Confidential Backup / Restore RMAN incremental backups can reduce the downtime Copy the backups to destination system Restore into the database Gotchas Heavy DML operations may prolong the Restore-Sync time Going through Tape can significantly add time to backup and restore Typically few restore (tape) resources are allocated Advantages Primary Database is up and running Can use RMAN compression, parallel operations RMAN only backups the changes and restores the needed files Tips Use a shared disk (NFS) between the target server If you have to go to tape, request dedicated backup channels until the restore is complete
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  • Global Marketing 16Confidential Transportable Tablespaces Create the empty database Create the Metadata of the source database in the new database Database files are moved from existing database to the other system Gotchas Source and target systems should have the same character set and national character set Limitations on indexes ( Function based/domain ) Limitations on snapshot/replication Tables and indexes to be part of the self contained set All the partitions of a partitioned table needs to be moved as a set Advantages Use this option to move the databases across different platforms Faster because it bypasses usual data extract and load processes Efficient than export/import
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  • Global Marketing 17Confidential Logical/Physical Standby Option Available for 10.1.0.3 and above Very minimal downtime( time to switchover ) Must setup a Data Guard environment Gotchas Need to modify Primary to setup Logical/Physical Standby OS must be the same ( family) between primary and standby Primary needs to be shut down for DB Upgrade on the target SQL Apply reapplies the transactions. Heavy OLTP systems are not a good candidate for Logical Standby Doesnt work for cross platform Advantages Proven technology Changes to the production are copied over to the standby Newer versions, you can use it to test the performance using snapshot standby Protection from Physical Corruption
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  • Global Marketing 18Confidential Only available for EMC Storage - Symmetrix Remote Data Facility Manages real time copies of data volumes ( at the storage level) Gotchas EMC solution for Symmetrix storage Physical corruption will get carried over to the other side The target (individual) Lun size should be equal to or larger than source Lun Advantages Most simple solution to copy multi-terra byte DBs Most of the work is on the storage team to setup SRDF SRDF can copy the incremental block changes after initial setup SRDF Copy Option
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  • Global Marketing 19Confidential ASM Rebalance Option Leverage ASM rebalance feature to off-load data from one storage array to another Gotchas Will require downtime to bring up the new system Will require downtime to perform DB upgrades Advantages No disruption to primary database during rebalance No monitoring or governance during the operation
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  • Global Marketing 20Confidential ASM Rebalance Option Storage Arrays 1. Add the New LUNs on the OLD system (OS) 2. Add the LUNs to the Disk Group 3. Perform Rebalance 4. Shutdown Old System 1. Create CRS,DB,ASM on new system 2. Copy SPFILEs (DB,ASM) 3. Add the New LUNs on the New system (OS) 4. Bring up the database
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  • Global Marketing 21Confidential Oracle Streams Little or no downtime Source and Targets can be any version to any platform Gotchas Limitations on some data types ( CLOB/BLOB) Extremely complex to implement & maintain Longer development cycles Need highly skilled DBAs Advantages Can be used to migrate between different platforms and versions
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  • Global Marketing 22Confidential Golden Gate Option Little or no downtime Source and Targets can be any version to any platform Gotchas Requires Golden Gate License investment of intermediate platform when moving from one OS Family to another Advantages Moderately complex to implement Provides Fall back options You can leverage the infrastructure many times Best near Zero Downtime Option
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  • Global Marketing 8i & 9i 10g/11g Migration Overview Goldengate Capture to Trails Create Clone DB via RMAN 8i/9i ASM Storage XTTS Transport Tablespace Goldengate Apply from Trails Real-Time Replication Fail back!Reverse Replication Server & Storage Provisioning DBA Begins Migration Production App Testing Switchover to RAC Database Fail back Strategy Post-Migration
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  • Global Marketing 24Confidential In place Migrations of OS Complete Downtime to the server being upgraded Data Guard can be up and running while the migration is taking place Operating System Upgraded wipes out internal drives Newer Cluster Version wipes out the Clusterware drives Data Luns inside ASM are intact.
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  • Global Marketing 25Confidential In place Migration Steps DBA 1. Create and save (elsewhere) pfile from the spfile Linux Engineer 1. Re-image all cluster nodes to new OS 2. Post-build steps an 11g RAC cluster. 3. Check and validate if the cluster is healthy and operational DBA 1. Restore the saved pfile configuration files and start ASM. 2. Mount the expected ASM disk groups and start the DB. 3. By starting the DB under the 11g binaries, this converted the 10gR2/64 DB to 11g. Run DB Upgrade script