Backup databases to Cloud – what you need to look for?


If you are involved in SQL Azure projects in your organisation then you will be aware of  SQL Server 2012 SP1 CU2 release update which has given the option to support for back to Azure  cloud storage right in the database engine. As the feature is a CU release and soon it will be incorporated in Service Pack 2 release, BOL reveals the advantage about this feature:

This feature can be used to backup SQL Server databases on an on-premises instance or an instance of SQL Server running a hosted environment such as Windows Azure Virtual Machine. Backup to cloud offers benefits such as availability, limitless geo-replicated off-site storage, and ease of migration of data to and from the cloud. In this release, you can issue BACKUP or RESTORE statements by using tsql or SMO. Back up to or restore from the Windows Azure Blob storage service by using SQL Server Management Studio Backup or Restore Wizard is not available in this release.

Not only that I will also recommend the method to use PowerShell to Backup Multiple Databases to Windows Azure Blob Storage Service method which is better to handle. However this is supported only from SQL Server 2012 SP1 CU4 release on wards. BOL refers to whole load of benefits in doing so, see below:

  • Creating off-site storage for your SQL Server backups can be as easy as modifying your existing scripts/jobs. Off-site storage should typically be far enough from the production database location to prevent a single disaster that might impact both the off-site and production database locations. By choosing to geo replicate the Blob storage you have an extra layer of protection in the event of a disaster that could affect the whole region. In addition, backups are available from anywhere and at any time and can easily be accessed for restores.
  • Backup Archive: The Windows Azure Blob Storage service offers a better alternative to the often used tape option to archive backups. Tape storage might require physical transportation to an off-site facility and measures to protect the media. Storing your backups in Windows Azure Blob Storage provides an instant, highly available, and a durable archiving option.
  • No overhead of hardware management:There is no overhead of hardware management with Windows Azure services. Windows Azure services manage the hardware and provide geo-replication for redundancy and protection against hardware failures.
  • Currently for instances of SQL Server running in a Windows Azure Virtual Machine, backing up to Windows Azure Blob storage services can be done by creating attached disks. However, there is a limit to the number of disks you can attach to a Windows Azure Virtual Machine. This limit is 16 disks for an extra large instance and fewer for smaller instances. By enabling a direct backup to Windows Azure Blob Storage, you can bypass the 16 disk limit.

    In addition, the backup file which now is stored in the Windows Azure Blob storage service is directly available to either an on-premises SQL Server or another SQL Server running in a Windows Azure Virtual Machine, without the need for database attach/detach or downloading and attaching the VHD.

There will be cost involved in the cloud storage backup strategy, but it is highly essential to see the Windows Azure Billing Considerations options. The Windows Azure pricing calculator can help estimate your costs. In any case we should not take this cloud storage backup as a replacement to local backup (on-premise databases) strategy. As you are putting up only the important data on cloud, not all of the data it is highly essential to ensure that local backups are always secure and faster than sending them on wire. There is a catch in terms of what is used within the data transfers, because all the usage on Cloud is charged based on the space used and calculated on a scale of redundancy level. So you need to consider the pricing structure agreement that you may have with Microsoft and also the inbound data transfers to Windows Azure are free and outbound transfers are calculated based on the scale of transfers.