Database Reference
In-Depth Information
The reason for allowing backups to a URL is to allow you to integrate your SQL Server
backups with cloud-based storage and store your backups in Microsoft Azure. You
saw in the irst chapter that you can now place your database iles on Microsoft Azure
cloud-based storage. By being able to create a backup there, you can keep database
backups of your on-premise database in Microsoft Azure. This makes your backups
safer and protected in the event that your main site is lost to a disaster as your backups
are stored offsite. This can avoid the need for an actual disaster recovery site.
In order to create a backup to
Microsoft Azure Storage
, you need a storage account
and a storage container. You have already learned how to create one of those back
in the previous chapter when the SQL Server Database ile was hosted on Microsoft
Azure Storage.
From a SQL Server perspective, you will require a URL, which will specify a
Uniform Resource Identiier
(
URI
) to a unique backup ile in Microsoft Cloud. It is
the URL that provides the location for the backup and the backup filename. The URL
will need to point to a blob, not just a container. If it does not exist, then it is created.
However, if a backup file exists, then the backup will fail. This is unless the
WITH
FORMAT
command is specified, which like in older versions of SQL Server allows the
backup to overwrite the existing backup with the new one that you wish to create.
You will also need to create a SQL Server credential to allow the SQL Server to
authenticate with Microsoft Azure Storage. This credential will store the name of the
storage account and also the access key. The
WITH CREDENTIAL
statement must be
used when issuing the backup or restore commands.
There are some limitations you need to consider when backing up your database to
a URL and making use of Microsoft Azure Storage to store your database backups:
• Maximum backup size of 1 TB (Terabyte).
• Cannot be combined with backup devices.
• Cannot append to existing backups—in SQL Server, you can have more than
one backup stored in a file. When taking a backup to a URL, the ratio should
be of one backup to one file.
• You cannot backup to multiple blobs. In a normal SQL Server backup, you
can stripe it across multiple files. You cannot do this with a backup to a URL
on Microsoft Azure.
There are some limitations you need to consider when backing up to the Microsoft
Azure Storage; you can find more information on this at
http://msdn.microsoft.
com/en-us/library/dn435916(v=sql.120).aspx#backuptaskssms
.
