RA-GRS allows you to have higher read availability for your storage account by providing "read only" access to the data replicated to the secondary location. Once you enable this feature, the secondary location may be used to achieve higher availability in the event the data is not available in the primary region. This is an "opt-in" feature which requires the storage account be geo-replicated. Reference: https://docs.microsoft.com/en-us/azure/storage/common/storage-redundancy