Storage accounts can set their replication settings to GRS (Geo-redundant storage) and RA-GRS (Read-access geo-redundant storage). 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 for protection in case of disaster in the primary data center. This is not a stable backup method for your data since changes made to the primary data will immediately be replicated to the secondary data center. This type of replication cannot be used as a safeguard against user or application error.
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. GRS does not allow read operations to the data, and can only be accessed if Microsoft fails over to the secondary data center (which would only occur in case of a disaster at the data center). RA-GRS accounts however can read from the secondary data center.
In most cases, geo-replication is not required and LRS (Locally-redundant storage) can be used. LRS makes three 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 wherein the entire data center is lost.
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 the recommendation
- Click View in Portal to open the Azure Portal on the correct resource.
- Select Configuration in the menu.
- Select LRS in the Replication drop-down.
- Click Save on the top header.