Making Backedup data zone aware

Question

Hi,

I am going to create a recovery vault i see only 2 storage replication options in west europe

1. LRS and 2. GRS

If my understanding is right, in the event of datacenter failure, my backup data residing the vault would be lost/corrupted if I set replication to LRS (since it only provide fault tolerance over H/W failure within datacenter replicated data 3 times)

I can't afford to go for GRS due to business limitations, Cost etc.

I at least need this data to be replicating to other datacenter within same Region, so, at least DC failure risk can be mitigated. unfortunately, zone redundant recovery vaults is not present in this Region (West europe)

what should be alternatives to mitigate a DC failure risk (considering my VMs and recovery vault are in the same availability zone )

although I can't see the availability zone of recovery vault unlike VMs

Answer 1

Ok. I must say it though. Backup is not DR. One way is to create the multiple VMs in different availability zones. In such case your application must be able to work fine if one of the VMs in one of the availability zones goes down. The backup cannot restore the VM to different zone. Even if you restore the disks the disks will be restored in the same availability zone. If you have enabled cross-region restore there you can restore to any availability zone but within that region.

Answer 2

Hi,
You are correct on those statements. I do not quite understand the issue with Azure Backup and availability zones. As per the official documentation. West Europe is a region with availability zones support. Also, on that page Azure Backup is listed as Resilient to the zone-wide outages which means that if there is failure in one zone Azure Backup will be functional. Of course, this means that you need to use GRS for storage type. There is no option for using LRS and the vault to be zone-redundant as these are mutually excluded.

Looking at your question I am not sure if you are looking for Disaster Recovery solution or for Backup solution. Both Azure Site Recovery and Azure Backup use the same vault resource, but they are two different services. For example, the choice between GRS and LRS applies only for the backup service, and it does not apply for the Site Recovery service.

Let's say you are using Azure Backup in West Europe and you have several VMs in West Europe that are in multiple availability zones. Suddenly there is a datacenter failure in West Europe which affects your Azure Backup vault but does not affect your VMs. The backup vault will be not possible to use so backups and restores will not be possible, but this will not affect your VMs. Probably in such kind of situation you do not want to do restores and backups you can compensate manually later when the datacenter is restored.

Please "Accept the answer" if the information helped you. This will help us and others in the community as well.

Answer 3

Hello @WinTechie - Thank you for your post!

Currently ZRS feature is available in UK south (UKS and South East Asia (SEA). ZRS by itself may not protect your data against a regional disaster where multiple zones are permanently affected. For protection against regional disasters, Microsoft recommends using geo-zone-redundant storage (GZRS), which uses ZRS in the primary region and also geo-replicates your data to a secondary region. Ref doc: https://learn.microsoft.com/en-us/azure/storage/common/storage-redundancy#zone-redundant-storage

---------------------------------------------------------------------------------------------------------------

If the response helped, do "Accept Answer" and up-vote it.