migrationoracleupgrade
I'm fairly new to Oracle databases and have been tasked with assessing the implications of upgrading our application's database from 11g to 12c.
I have managed a successful in-place upgrade but a number of stakeholders will be looking to upgrade to new hardware so I need to access the viability of a migration upgrade.
Is it possible to migrate the current active database to a fresh installation of 12c and which would be the most effective method for this?
For speed (eg less downtime) backup/restore. Backup/restore is quicker because of Instant File Initialisation (only for MDF). The actual backup file is a lot smaller then the MDF/LDF sizes so copies quicker.
It's arguably slighty less risky because there is no downtime on the SQL 2000 instance.
However, detach removes access to the old database. You'll have to take this offline with a backup/restore. If there is a risk of end users connecting, use this (or take offline as soon as backup is complete)
Basically, it's whatever suits you best. I've used both methods for a recent server migration.
The foremost step to do is to run the Upgrade Advisor on SQL Server 2000 database and address all the issues reported by it.
As a best practice, use the Upgrade Advisor tool on your SQL Server 2000 legacy database and import a trace file to the Upgrade Advisor tool for analysis. The trace file lets the Upgrade Advisor detect issues that might not show up in a simple scan of the database, such as TSQL embedded in applications. You can capture traces of TSQL using SQL Profiler on your SQL Server 2000 server during typical hours and analyze these traces using the Upgrade Advisor.
So the rest of the steps would be :
On the day of migration :
DBCC CHECKDB ('<db_name_goes_here>' ) WITH ALL_ERRORMSGS,NO_INFOMSGS, DATA_PURITYDBCC UPDATEUSAGE('database_name') WITH COUNT_ROWSUpdate Statistics table_name with FULLSCANsp_recompile 'procedureName'SP_REFRESHVIEW view_nameIn SQL Server 2005 and up, Database Mail was introduced. So you have to migrate from SQLMail to Database Mail.
USE [master]
GO
sp_configure 'show advanced options',1
GO
RECONFIGURE WITH OVERRIDE
GO
sp_configure 'Database Mail XPs',1
GO
RECONFIGURE
GO
Also, if you have any replication, then you have to reset it up. If any DR like logshipping or Mirroring (new in 2005 and up, but depreciated in 2012) then you have to reset it up as well.
Old DTS packages needs to be migrated to SSIS using C:\Program Files\Microsoft SQL Server\100\DTS\Binn\DTSMigrationWizard.exe (command line) or using Package Migration Wizard.
Also, you can use my script found at https://dba.stackexchange.com/a/36701/8783. Though, it uses detach/attach method, I highly recommend you to use BACKUP/RESTORE method. Change the script accordingly.
As a side note:
Lets address your questions ...
What else should I do to make migration complete?
Refer to my answer. It will help you properly come up with a migration plan. Always test your migration plan in a UAT (non production) along with proper application testing by business users.
use new features like checksumming and full recovery model.
CHECKSUM is new in SQL Server 2005 and up. I have covered it as a part of migration steps described above.
full recovery model is not new. It depends on your business type and dictates on how much data you can lose in case of disaster.
Full recovery mode with frequent Transaction log backups will allow you to restore point-in-time and there by reducing the amount of data loss.
make this database to be exactly as it was created in SQL Server 2008 R2.
make this database to be fully compatible, correct and be perfect suited for new, SQL 2008 R2 database engine.
Don't fully understand this ! But above migration steps will help you. You just have to restore the database and change the compatibility level 10 100 along with above steps.
I just want to know how to correctly and completely convert old SQL Server 2000 database to new 2008 R2 database, be calm that everything is done right and be happy with all new features.
You have to be careful with this, as this will require changes to your application code as well. If your application code is changed to use the new features in SQL Server 2008 R2, then you wont be encountering any issues - PROVIDED you have fully done a complete regression testing of your application in a UAT or DEV environment. This will give you best confidence when you do the actual migration in PROD.
Note: Above are steps that I could remember and I am pretty sure that nothing is left out. If I see that I have missed some stuff, then I will add it or other experts on this site -- feel free to add !
Everything that is outlined above needs to first replayed on a NON PRODUCTION environment to avoid any surprises during the actual migration.
Few more questions:
You recommend to use backup/restore method, but I did as written above, so can I encounter any problems now? Everything worked without any problem.
If everything worked fine and you were able to attach the database, then NO you wont be having any problems. Detach/Attach vs Backup/Restore is just a method on how you move your database/s to a different place. Just FYI .. Backup/Restore is more secure and reliable as if anything goes wrong (in worst cases) then atleast you have a backup to restore and recover your database/s.
About checksumming and full recovery model: it wasn't available/enabled on SQL Server 2000, so I want to use them now. You said that the only thing I need to do is to enable those options in database properties? I've read somewhere, that it isn't enough and I should also rebuild indexes or something. I really don't know, I just asking.
As I said, checksum is new in version 2005 and up. It is a mechanism by which SQL Server will detect page corruption especially due to I/O. Refer to my answer here for more details.
To enable CHECKSUM as well as change the recovery model to FULL, you can do it using below T-SQL code :
USE master;
GO
ALTER DATABASE [your_database_name] -- change this !!
SET RECOVERY FULL, PAGE_VERIFY CHECKSUM;
GO
Note : Once you set the database options, it will be persisted when you do migration from 2008R2 to 2012.
I'm preparing to migrate this database to SQL Server 2012 - so first it was from 2000 to 2008 R2, now it will be from 2008 R2 to 2012 (it was impossible to do this directly because of lack of support of 2000 databases in SQL Server 2012). So I understand that I should follow your guide: backup it in 2008 R2 and restore in 2012, then do the rest of your tips, right?
Yes please. As I said, backup restore is the preferred method, unless you have a good reason not to do it.
Please explain me the backup/restore method: Is it like a dump of database to SQL queries and then restoring it by executing a bunch of queries? Will this method by the way "defragment" my database? If not, how to defragment/optimize it manually?
Backup/restore is ... similar to dump and load used in Sybase, Oracle or probably MySQL as well. Its just SQL Server calls it .. backup/restore.
A must read : Understanding SQL Server Backups by Paul Randall.
Simple Syntax(for Full syntax refer BOL) :
backup database database_name
to disk = 'D:\backup\database_name_full.bak'
with init, stats =10
Then restore can be done on destination server as :
-- assuming the destination's disk layout doesn't match the source server's
restore database database_name
from disk = 'D:\backup\database_name_full.bak'
move 'logical_data_fileName' to 'physical_path\database_name.mdf'
move 'logical_log_fileName' to 'physical_path\database_name_log.ldf'
with recovery, stats = 10
-- assuming the destination's disk layout matches the source server's
restore database database_name
from disk = 'D:\backup\database_name_full.bak'
with recovery, stats = 10
Will this method by the way "defragment" my database? If not, how to defragment/optimize it manually?
backup/restore will not defragment your database. You have to use Alter Index Reorganize or Rebuild depending on your fragmentation level.
Since you are new to SQL Server I would highly recommend you to use Ola Hallengren's :
As we were using SQL Server 2000 Express for years (no management interface), we were doing backups simply by stopping engine and RAR the DATA directory. For now, as we are on SQL Server 2008, isn't this still better than using backup function in Management Studio?
Stopping engine is the worse thing that you can do to do a backup !!
Read Paul's link about the backups that I mentioned and Use Ola's script. Microsoft has a KB article with the script to do automated backups - How to schedule and automate backups of SQL Server databases in SQL Server Express
Full recovery mode with frequent Transaction log backups - Where is the Transaction log stored - is it the LDF file? How sould I backup it properly?
Every SQL Server database has a log that records all the transactions and database modifications made by each transaction. The transaction log is a critical component of any database.
The usual naming convention extension for Transaction log is '.LDF', but it can be any.
I am not going to write more on this as this will make the answer very leanthy. Refer to Transaction Log Management and my answer here has excellent links as well.
If you are migrating your entire instance from one version to another version, I would highly recommend to use PowerShell based solution Start-SqlMigration
Best Answer
You can use
expdpandimpdputility by Oracle for migration of database from 11g to 12c.First of all we will use expdp utility to export the whole database into a dumpfile (.dmp) by issuing the following command:
Here, FULL parameter indicates that the whole database will be exported Directory --> The directory on server in which you want to place the dumpfile DUMPFILE --> The name of dumpfile LOGFILE --> The name of logfile (that logs the status of export process)
After the export is done successfully you will get something like:
Job "SYSTEM"."SYS_EXPORT_FULL_01" successfully completed at 10:35Now, your whole database is stored in a dumfile(.dmp) in the 'DIRECTORY' mentioned in the expdp command.
We will now start import of the database into 12c database with the help of impdp utility.
*Before starting import you might need to transfer the dumpfile to the new server (i.e. 12c)
After import has been successfully completed you will get successfull completion message.
Reference link --> https://oracle-base.com/articles/10g/oracle-data-pump-10g
Happy Migration !!