Two of the biggest advantages of the cloud are the high levels of availability and data protection that it provides. Azure is one of the most used cloud providers, especially for Windows-centric organizations.
Azure provides tight integration with many of Microsoft’s on-premise offerings. In addition, while cloud availability is not perfect, its uptime and data protection capabilities exceed the vast majority of private on-premise implementations. As Microsoft states in their SLA summary for Azure services, most Azure services like Azure Active Directory, Analysis Services, and Backup are guaranteed to provide 99.9% uptime. Other offerings like Cloud Servers and Virtual Machines that have two or more instances deployed in the same Availability Set are guaranteed to provide 99.95% availability. Let’s have a closer look at Azure storage and its built-in DR data protection capabilities.
Azure Storage Option
First, it’s important to understand Azure’s different storage options. Azure provides three types of file storage as well as NoSQL and relational SQL database storage.
- Azure Blob (Binary Large Objects) Storage can be used to store any type of text or binary file data including documents, photos, and VHD/VHDX files. Azure provides two types of blob storage: page blobs and block blobs. Page blobs provide persistent block storage and like Amazon’s EBS and they are optimized for representing Virtual Machine VHDs or Cloud Services drives. Block blobs provide object storage like AWS S3 and they are optimized for streaming and storing cloud objects like documents and media files.
- Azure Premium Storage uses page blobs on SSD-based storage to provide high IOPS and low latency. Azure Premium Storage is offered in three fixed sizes of 128GB, 512GB, and 1TB. It is priced using a flat monthly fee no matter how much storage you actually consume.
- Azure File Storage offers continuous availability storage that is similar to Amazon’s EFS. This file storage option is like a standard file share and it’s primarily designed to allow data to be shared between cloud applications as well as multiple VMs.
- Azure SQL Database is a PaaS relational database offering that’s very similar to on-premise SQL Server. As a PaaS offering the administration of the system resources is managed by Microsoft. Active geo-replication creates up to four online (readable) secondaries in any Azure region.
Azure Redundant Data Protection
One of the biggest advantages of the cloud is the fact that is able to provide geographical site protection on a global scale. The data in your Microsoft Azure storage account is always replicated to provide protection and high availability. The pricing for Azure storage is based on the type of storage selected, the amount of storage used and the redundancy option that you choose when you create your Azure storage account. You can select one of the following replication options:
- Locally redundant storage (LRS) – The least expensive option, LRS provides three copies of data within a single data center. This protects from hardware failure but offers no protection for a data center disaster.
- Zone-redundant storage (ZRS) – ZRS extends the protection of LRS by storing three copies of data across multiple data centers throughout a region. It is only applicable for block blob object storage.
- Geo-redundant storage (GRS) – Providing a much higher level of data protection, GRS distributes six copies of data evenly throughout two data centers in two separate regions – three in each region. GRS provides protection from local hardware failure as well as a Microsoft datacenter outage.
- Read-access geo-redundant storage (RA-GRS) – The highest availability Azure storage option, RA-GRS, extends standard GRS by allowing immediate read access to data stored in the secondary region from a secondary endpoint in the event that the primary region is unavailable.
Understanding the different Azure storage options and the types of data replication and protection options that are available can help you to optimize your Azure cloud DR capabilities. You can change the replication type of your storage account using the Azure portal or PowerShell as well for those that like to live in the command-line interface.