Introduction to the local redundant storage of Windows Azure storage

We are honored to provide two types of redundant storage for Windows http://www.aliyun.com/zixun/aggregation/13357.html >azure: Locally redundant storage and geographically redundant storage.

Local redundant storage (LRS) provides high durability and availability storage in one location (sub zone). As described in our SOSP monitors, we maintain an equivalent equivalent of 3 copies (replicas) of data in your primary location. This ensures that we can recover from common failures (disks, nodes, racks) without impacting your storage account availability and durability. All stores are synchronously written to three copies of three separate failed domains before successfully returning to the client. If there is a major datacenter disaster and a part of the data center is lost, we will contact the customer about potential local redundant storage data loss by using the customer's subscription contact information.

The geographically redundant Storage (GRS) provides us with the highest level of durability by storing your data in a second location (sub area) hundreds of miles away from the primary location area. All Windows Azure blobs and table data are backed up (geo-replicated) at different locations, but the queue data is not geo-replicated. By geographically redundant storage we maintain your data at the primary and secondary locations of 3 copies (replicas). This ensures that each datacenter can recover from common failures and provides data geo-replicated to prevent major disasters. In LRS, data updates are committed to the primary location before successful return to the client. Once completed, these updates are asynchronously geo-replicated to the secondary location through GRS.

All existing storage accounts in the current production process enable geographically redundant storage by default. You can choose to disable it by shutting down Windows Azure Portal geo-replication. You can also configure redundant storage options when you create a new account through Windows Azure portal.

Billing Details: The default storage is a geographically redundant storage, and its current price does not change. The current GRS price is the same as the price before the change was announced. With these changes, we are pleased to announce that the local redundant storage rates (23% to 34% depend on how much data is stored). Note that if you close geo-replication and then enable geo-replication, this operation will charge a one-time bandwidth fee to guide you from the primary to its secondary location. The amount of bandwidth charged at boot time equals the amount of data in the account that you store at boot time. The price of the boot bandwidth is the egress (outbound data transmits) rates for the account you are storing for the region (zone). Once the boot is complete, copying your data from the primary location to the secondary location will have no additional bandwidth cost. Also, if you use GRS from your storage account (created), we will not charge a boot bandwidth fee.

Some customers can choose to store locally redundant storage that does not require additional geographically redundant storage durability and wants to benefit from discounted prices. This data is usually divided into: (a) non-critical or temporary data (such as logs), and (b) data that can be recreated if it is lost from the storage source. An example of the latter is a coded media file that can be recreated from the Golden bits--store in another Windows Azure storage account that uses geographically redundant storage. In addition, some companies have geographical restrictions on which countries their data can be stored, and the choice of locally redundant storage ensures that the data is stored only in locations selected from the storage account.

Monilee Atkinson and Brad Calder