My collegue Mr. Makoto Miura (Makoto-san) from Japan wrote a wonderful blog for Japanese ECN Community and the blog has also garnered a viwership of more than 100 views. I thought of translating the blog from Japanese to English for the benefit of English readers and so I am presenting the good blog on Storage based backup which was originally written by Makoto-san. The translated blog was also reviewed by Makoto-san and so I convey my utmost gratitude to him.

 

I have been working in EMC Japan for more than 8 years but still I encounter and ponder about different special techniques to take the storage based backups (when I work with my customers). Can we take the backup of Oracle Database through the storage?  Can’t this backup be taken in some special ways or techniques?   I keep on thinking on this issue profoundly.

 

Luckily, at that time I was in a conversation with a customer. Though the discussion was very fundamental yet I thought on my own and tried to consolidate and conclude some points on this issue. Hence, I am writing this bog.

 

What is a storage based backup?

Among  various storage array backup techniques, Point in Time copy of Data is one of the technique.  By physical copy we perform the cloning while by logical copy of data we create snapshots. At the time of Cloning, the mirror volume of the RAID-1 can be dynamically attached or detached from the server.

I am not touching over above topic in greater detail, but I would like to say that both Snapshot and Clones are useful in different situations .Furthermore, from clones we can get different snapshots for different time period while we can use snapshots and clones in combinations. In storage backup we will get high speed processing without consuming too much of server or network resources. In addition, test, dev, QA environments can re-use the data in a much faster way . These are some of the many important and useful features of Storage based Backups.

 

Is it possible to perform online backup?

Of course , it is absolutely possible. After offlining the Oracle database, copy of the storage array is possible. Even if the database is online, the copy operation of the storage array of the Oracle database is also possible as well.

 

What are the different official way of Oracle to take the DB backup?

So far as online backup of Oracle is concerned, invariably, it can be done in 2 ways:

 

  • User managed Backup
  • RMAN Backup

 

User managed Backup can be used in combination with the storage based backup. The standard process for the usage of user managed backup is illustrated below:-

 

  1. BEGIN hot-backup.
    • SQL > ALTER DATABASE BEGIN BACKUP;
  2. Copy data files
  3. END hot-backup
    • SQL > ALTER DATABASE END BACKUP;
  4. Archive current Redo Log
    • SQL > ALTER SYSTEM ARCHIVE LOG CURRENT;
  5. Copy the latest archive log for recovery
  6. Backup control files
    • SQL > ALTER DATABASE BACKUP CONTROLFILE TO TRACE;  (text format)
    • SQL > ALTER DATABASE BACKUP CONTROLFILE TO 'XXX'; (binary format)

 

I am using the User managed Backup right from the days of Oracle 7. During that time, we used the copy command as mentioned in Item 2 above. As of now nothing has changed so far as storage based backup processes are concerned. However, there is only one change now and the change is that the database copy used to take a long time earlier but now if the Step 2 (above) copy is done via storage layer then it can be completed almost instantly.

In EMC, a tool called Replication manager is available for automating the database storage backup process via a script. By Replication Manager, we need not create a manual script instead we can connect automatically via the GUI console. It follows the steps mentioned above. Furthermore, the backup copy can be transferred automatically into a separate host mount or any listed host from the tool. For detailed explanation and functionality, pls. consult White Paper: EMC Replication Manager Integration with Oracle Database Server — A Detailed Review.

 

Can we use both RAC and ASM together for backup?

Yes, we can take the backup of the both in the same traditional forms. Using Replication manager is also beneficial.

 

Is there any other convenient mode to take the backup?

Storage copy is most convenient mode of backup here. Below are some examples.

 

 

    • Again after using 12c’s Storage Snapshot Optimization technique, the database copy (without using Hot Backup) becomes much easier than the traditional methods of roll forward by using manual commands.

 

  • Disaster Backup Plan
    • The remote copy backup of the storage is possible for  oracle DB’s remote copy backup and is very easy and time savings. I am not going into the details here but by this method we can backup multiple instances simultaneously. Data Guard can be used as a remote backup solution especially during critical times. Finally, storage based backup process has been depicted in the below figure in a step by step fashion

 

aa1.bmp.jpg

I talked a lot to the customers regarding different modes of backups and I realize that almost everyone gets into some form of trouble during different backup stages. Especially when it is 24 * 7 mission critical environments, people use back-end backups and many get into problems with multiple error messages mentioned in the log file. I am looking into the different oracle solutions which may be helpful here. Henceforth, in every meeting with the customers, I will try to notice and understand the different issues on the backup stuff from customers perspective and would like to document the same through future blogs.