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Azure Storage Accounts as backup repositories and offsite copies + egress topic

  • 12 July 2023
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Userlevel 3
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Hello community,

I’m wondering about cloud libraries redesign to provide offsite copies for resources protected in certain Azure region.

 

Since we don’t have express route in our configuration, I’m wondering how to keep costs low. Basically, we are running at Metallic, but most of Commvault configuration is available to us.

 

So, there are two major scenarios I’m considering:

  • use set of new AZ Storage Accounts with native Geo replication (GRS) to keep egress costs more controlled. So there would be primary copy keep at hot LRS in RegionA and secondary at cool GRS RegionA (replicated to paried region)
  • use Commvault native auxcopy, this will trigger significant egress upon transferring data from one AZ region to another due to extensive data reads. So there would be primary copy keep at hot LRS in RegionA and secondary at cool LRS RegionB 

 

What are you experiences? Will GRS with additional amount or reads caused due sFull etc. generate significant additional costs too? Or maybe there’s something I’m missing, like another option worth considering?

 

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Best answer by Damian Andre 13 July 2023, 04:14

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Userlevel 7
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Hey @Lukas3D,

Check out the azure cloud architecture guide - some great guidance in there regarding storage.

I hope I understood your question properly… but here it goes:

GRS wont generate any egress costs by being inherently redundant. The cost is factored in with a higher per GB cost to account for the replication that is happening. The replica copy is almost invisible to you - all managed under the covers by Azure (I do believe you can access it in read-only mode). Upon failure the use of the replicated copy happens automatically so you don't have to adjust your application. Think of this like a Raid1 mirror.

One thing to keep in mind is that a Commvault copy is truly independent - you can have separate retention etc. With Azure its more of a dependent mirror of your data - Accidentally delete a job on the primary copy - and its gone from the replica. Not so with a Commvault copy.

So I think they both accomplish different things. GRS is more of a protection from hardware failure, natural disaster on your primary copy, whereas a Commvault copy provides more protection from deletion, ransomware etc.

Userlevel 3
Badge +5

Hey @Lukas3D,

Check out the azure cloud architecture guide - some great guidance in there regarding storage.

I hope I understood your question properly… but here it goes:

GRS wont generate any egress costs by being inherently redundant. The cost is factored in with a higher per GB cost to account for the replication that is happening. The replica copy is almost invisible to you - all managed under the covers by Azure (I do believe you can access it in read-only mode). Upon failure the use of the replicated copy happens automatically so you don't have to adjust your application. Think of this like a Raid1 mirror.

One thing to keep in mind is that a Commvault copy is truly independent - you can have separate retention etc. With Azure its more of a dependent mirror of your data - Accidentally delete a job on the primary copy - and its gone from the replica. Not so with a Commvault copy.

So I think they both accomplish different things. GRS is more of a protection from hardware failure, natural disaster on your primary copy, whereas a Commvault copy provides more protection from deletion, ransomware etc.

 

Thank you Damian, I have read this and its valuable document. So, everything is clear now, GRS will do the job. 

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