none
Azure related to storage replication (Option definition clarification) and availability Questions

    Question

  • In Azure, when we choose blob storage or table storage, we have choose of replication

    We want to the most availability -- for 99.999% service support.

    There are two requirements we want to meet

    a) Redundancy -- data should be replicated not just within local DC, but cross DCs for most availability

    b) Data replicated across the DCs can't cross the Region : Say north America data can't be stored / copied to European DCs.

    Q = for above availability, what replication option we should choose, it is not clear from existing Azure documentation to see what "GEO" means, and we don't want JUST LOCAL DC redundancies either

    My second question is:

    When I create storage which has 500 T size... for reliability and availability point of the view, is multiple storages better than a single storage (note, will all choose proper 3 copies or Geo replication based on previous answer) or SAME?

     Thanks

    Wednesday, May 27, 2015 6:03 PM

Answers

  • Hi,

    1. When you choose Geo-Redundant Storage, it means your data is replicated thrice within the primary region and thrice in a secondary region , providing the highest level of durability. In the event of a failure at the primary region, Azure Storage will failover to the secondary region. It ensures that your data is durable in two separate regions.
      If you are using Block Blobs you could also try
      Zone-redundant storage. It replicates your data across two to three facilities, either within a single region or across two regions, providing higher durability than Locally Redundant Storage. If your storage account has ZRS enabled, then your data is durable even in the case of failure at one of the facilities. Also Note that once you have created your storage account and selected zone-redundant replication, you cannot convert it to use to any other type of replication, or vice versa.You could refer the following link for details on various Azure Storage Redundancy options and the list of Primary and Secondary region pairings:https://azure.microsoft.com/en-us/documentation/articles/storage-redundancy/
    2. I guess the above would answer your second question as well. If you opt for GRS, you can create a single storage and store your data. If you opt for ZRS, you might want to consider multiple storages instead of one.

    Hope this answers your query.

    Regards,
    Malar.

    Thursday, May 28, 2015 10:54 AM