You are building a database backup solution for a SQL Server database hosted on an Azure virtual machine.
In the event of an Azure regional outage, you need to be able to restore the database backups. The solution must minimize costs.
Which type of storage accounts should you use for the backups?
In the event of an Azure regional outage, it is crucial to ensure your backup solution remains available and can be restored. Geo-redundant storage (GRS) replicates data to a secondary region, providing protection against regional outages. Since minimizing costs is also a priority, GRS is the better choice over read-access geo-redundant storage (RA-GRS) because it is less expensive. While RA-GRS offers immediate read access to the secondary region, GRS can still ensure data restoration with a manual or Microsoft-initiated failover, thereby fulfilling the requirement to restore the backups after a regional outage.
According to Microsoft, "Geo-redundant storage (with GRS or GZRS) replicates your data to another physical location in the secondary region to protect against regional outages. However, that data is available to be read only if the customer or Microsoft initiates a failover from the primary to secondary region. When you enable read access to the secondary region, your data is available to be read at all times, including in a situation where the primary region becomes unavailable. For read access to the secondary region, enable read-access geo-redundant storage (RA-GRS) or read-access geo-zone-redundant storage (RA-GZRS)." So, if Primary Region is unavailable and MS did not failover, then you can only restore Backup on secondary region if it is RA-GRS.
so, the answer should be D, GRS?
Assuming the primary region is not available and both MS and yourself can NOT initiates a failover, that means your data on secondary region is not readable if you use GRS. But RA-GRS is always readable. So the answer is B, RA-GRS.
If this was true GRS would be almost useless.
You can do the failover yourself on a GRS account, so technically GRS minimizes costs. That said, if you have a solution where all this DR is required, you'd almost certainly want RA-GRS for testing/verification. The cost difference is minimal (yes, the costs add up if you have tens of TBs of backups, but would represent only a very tiny percentage of the costs needed to run an app/db of this size). So again technically GRS but realistically you would select RA-GRS.
Key here is minimizing the cost so GRS serves the purpose. Here they are not talking about always Read its all about having a backup ready and cheaper.
The difference between GRS and RA-GRS: GRS - After failover, the read-only is available. If no failover, it can not be readable. RA-RGS - is always enable and read-only. If GRS is cheaper, D is the right answer.
That's correct: "Geo-redundant storage (with GRS or GZRS) replicates your data to another physical location in the secondary region to protect against regional outages. However, that data is available to be read only if the customer or Microsoft initiates a failover from the primary to secondary region. When you enable read access to the secondary region, your data is available to be read at all times, including in a situation where the primary region becomes unavailable. For read access to the secondary region, enable read-access geo-redundant storage (RA-GRS) or read-access geo-zone-redundant storage (RA-GZRS)." Answer would be d since GRS is cheaper than RA-GRS
Answer is correct: B. https://medium.com/@aslanim/azure-accessing-your-sql-server-backups-in-your-ra-grs-account-17e0c7457146
D is correct as it is the cheaper option. Key word "minimize" costs.
B. read-access geo-redundant storage (RA-GRS) The ask is to "building a database backup solution" so we need to be able to test the solution https://docs.microsoft.com/en-us/azure/storage/common/storage-redundancy If your storage account is configured for read access to the secondary region, then you can design your applications to seamlessly shift to reading data from the secondary region if the primary region becomes unavailable for any reason. The secondary region is available for read access after you enable RA-GRS or RA-GZRS, so that you can test your application in advance to make sure that it will properly read from the secondary in the event of an outage. For more information about how to design your applications to take advantage of geo-redundancy
... and what else is being asked?? "minimize costs"
Azure Storage supports account failover for geo-redundant storage accounts. With account failover, you can initiate the failover process for your storage account if the primary endpoint becomes unavailable. The failover updates the secondary endpoint to become the primary endpoint for your storage account. Once the failover is complete, clients can begin writing to the new primary endpoint. Geo-redundant storage (GRS) or geo-zone-redundant storage (GZRS) copies your data asynchronously in two geographic regions that are at least hundreds of miles apart. If the primary region suffers an outage, then the secondary region serves as a redundant source for your data. You can initiate a failover to transform the secondary endpoint into the primary endpoint. https://docs.microsoft.com/en-us/azure/storage/common/storage-disaster-recovery-guidance
Answer is D. b/c, the use case says; "due to Azure regional outage, you need to be able to restore the database backups."
how come RA-GRS can be cheaper as this is a addon to provide access to data in secondary region even there is no outage in primary region. GRS should be cheaper as it replicates data and only accessible once primary region has an outage. Read the below from MS. With GRS or GZRS, the data in the secondary region isn't available for read or write access unless there is a failover to the secondary region. For read access to the secondary region, configure your storage account to use read-access geo-redundant storage (RA-GRS) or read-access geo-zone-redundant storage (RA-GZRS) In extreme circumstances where a region is lost due to a significant disaster, Microsoft may initiate a regional failover. In this case, no action on your part is required. Until the Microsoft-managed failover has completed, you won't have write access to your storage account. Your applications can read from the secondary region if your storage account is configured for RA-GRS or RA-GZRS.
Disregard my comment about ZRS being the correct solution. As they note in the answer the copies made in the different zones are all in the same REGION. Here we are presented with a regional outage so ZRS will not suffice.
Geo-redundant storage (GRS) copies your data synchronously three times within a single physical location in the primary region using LRS. It then copies your data asynchronously to a single physical location in a secondary region that is hundreds of miles away from the primary region. GRS offers durability for Azure Storage data objects of at least 99.99999999999999% (16 9's) over a given year.
I've researched it myself and read the comments ... I'm sticking with B (RA-GRS) - I think the addition of "minimize cost" is a trick especially since this scenario relates to Azure VMs. If the scenario mentioned "failover" I'd be inclined to pick D (GRS).
ChatGPT - C.ZRS
Correct answer is D: It's cheaper. Both GRS and RA-GRS replicate data to a secondary region, providing redundancy in the event of a regional outage. RA-GRS additionally allows read access to the secondary region, which can be useful for disaster recovery scenarios. However, RA-GRS accounts are more expensive than GRS accounts.
I think the answer is D. Because D cheaper than B.
D is correct. "Geo-redundant storage (with GRS or GZRS) replicates your data to another physical location in the secondary region to protect against regional outages. However, that data is available to be read only if the customer or Microsoft initiates a failover from the primary to secondary region. When you enable read access to the secondary region, your data is available to be read at all times, including in a situation where the primary region becomes unavailable. For read access to the secondary region, enable read-access geo-redundant storage (RA-GRS) or read-access geo-zone-redundant storage (RA-GZRS)." https://docs.microsoft.com/en-us/azure/storage/common/storage-redundancy#read-access-to-data-in-the-secondary-region In the question's scenario, a failover to another region *is* required, so GRS is suitable. GRS is also a bit less expensive than RA-GRS.
Only D. geo-redundant https://docs.microsoft.com/en-us/azure/architecture/resiliency/recovery-loss-azure-region#recovery-by-using-geo-redundant-storage-of-blob-table-queue-and-vm-disk-storage
My two cents... In the event of an Azure regional outage, you need to be able to restore the database backups. The solution must minimize costs. Which type of storage accounts should you use for the backups? A. locally-redundant storage (LRS) B. read-access geo-redundant storage (RA-GRS) C. zone-redundant storage (ZRS) D. geo-redundant storage MINIMIZE COSTS = Zone redundant storage Local redundant doesn't help when there is a regional outage. RA-GRS is not useful for the restores geo-redundant is not the most cost effective
region failure would mean all zones are failed
has to be geo