Storage accounts can set their replication settings to GRS (Geo-redundant storage) and RA-GRS (Read-access geo-redundant storage). In fact, GRS is the default option when creating a new storage account in the Azure portal. Both of these settings will make additional copies of the data stored in the account to a secondary data center in case of disaster in the primary data center. Please note that is not a durable backup of your data. Any changes made to the primary data will immediately be replicated to the secondary data center. As such, this type of replication cannot be used as a safeguard against user or application error.
In most cases, geo-replication is not required and LRS (Locally-redundant storage) can be used instead. LRS already makes 3 copies of the same data within different locations of a single data center. As such, it is highly unlikely that the data be lost. The only situation where data loss can happen permanently is in a disaster situation where the entire data center is lost.
Additionally, using GRS or RA-GRS will slow down write operations to the storage account since the data must be replicated to the secondary data center for each operation. Finally, GRS does not allow read operations to the data and can only be accessed when and if Microsoft fails over to the secondary data center in case of disaster. RA-GRS accounts however can read from the secondary data center.
To trigger this recommendation, a storage account must fill the following criteria:
- Storage account must be set to GRS or RA-GRS replication.
- Storage account must not be empty.
How to apply
Step 1: To apply this recommendation, click on "View in Portal" to open the Azure Portal on the correct resource.
Step 2: To change the replication type, click on "Configuration" in the menu and select LRS in the Replication drop-down:
Step 3: Click on "Save" in the top header.