Saturday, April 19, 2014

Oracle Database Backup Service explained

Oracle databases are commonly used for mission critical systems, in many cases databases are configured in a high availability setup spanning two or more datacenters. Even though a dual or triple datacenter is protecting you against a number of risks, like for example a fire in one of the datacenters it is not excusing you from implementing a proper backup and recovery strategy. In cases where your data is corrupted or for any other reason you need to consult a backup you will most likely rely on Oracle RMAN. RMAN used the default way for backup and recovery and ships with the Oracle database.

The below diagram shows a proper way of conducting backups. In this case all the data in database A and B is written to the tape library in another datacenter. Databases C and D write the data to the other datacenter. This ensures that your data is always at two locations. If for some reason datacenter-1 should be considered a total loss you can still recover your data from the other datacenter. For mission critical systems you most likely also will have a standby database in the other datacenter however this is not included in this diagram.

Even though this is considered a best practice it is for some companies a costly implementation. Specially smaller companies do not want to invest in a dual, or even triple, datacenter architecture. For this reason you commonly see that the data is written to tape in the same datacenter as the database is hosted and that a person is collecting the tapes on a daily basis. Or, in some worst case scenarios the tapes just reside in the same datacenter. This holds that in case of a fire the entire data collection of a company can be considered lost.

Oracle has recently introduced a solution for this issue by adding a cloud backup service to its cloud services portfolio. The Oracle database backup cloud provides an option to keep using your standard RMAN tooling, however instead of talking to a local tape library, or one in another datacenter, you will be writing your backup to the Oracle cloud. This cloud service, named Oracle Database Backup Service requires you to install the Oracle Database Cloud Backup Module on your database server. You can use the installed module as a RMAN channel to do your backup. By using encryption and compression you can ensure that your backup is send quickly and secure to the Oracle backup Service.

The above diagram shows the flow used in case you backup to the Oracle database backup service. This model is working when you have, for example, only a single datacenter. However it can also work as a strategic model when you have multiple datacenters and even if you have mixed this with cloud based hosting.

The above diagram shows how you can use the Oracle database backup service to do a cloud to cloud backup. If you, for example, host your database at Azure or Amazon and you would like to backup your data at the same backup service providers as all your other datacenters are using. Or you want to have it at Oracle to ensure your data is not with one single company, you can use the same mechanism to perform the backup to the Oracle Database Backup Service.

Creating an account at Oracle and ordering backup space is easy and can be done completely online. As you can see from the screenshot below you can order per terabyte of backup space.

One thing you have to keep in mind, as with all cloud based solutions. There are some legal considerations you need to review. When using the Oracle Database Backup Service you are moving your data away from your company and into the trust of another company. Oracle has provided numerous security options to ensure your data is safe, however, from a legal point of view you have to be sure you are allowed to move the data into the trust of Oracle. For most US based companies this will not be an issue, for US based government agencies and non-US companies it is something you might want to check with your legal department, just to be sure.

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