How to estimate cost and performance of on-prem SQL Server backups to Azure Storage

Question

Hi,

I am researching the possibility of moving on-prem SQL Server backups to Azure Blob Storage. I would like to use the backup and restore from URL option available on SQL Server, to be able to use Azure Blob Storage. However, I am not about two major aspects of this aproach.

Firstly, the cost - I read somewhere that SQL Server backup to Azure URL will use the PutBlob operation with 4MB block size. Does this mean, that if I have a 50GB backup, then the backup operation would take 50 000Mb/4Mb = 12 500 write operations/api calls? And then when it comes to the restore from URL operation, does it work the same way i.e. 12 500 read api calls?

Secondly, the performance - how do I estimate how long will the backup and restore operations take? Is there a way to reliably estimate the speed? For example if I have an RTO of 3 Hours how can I make sure I will be able to recover the backup in time?

Thanks in advance !

Answer 1

Hi @Bruno Kozakowski-Kędzierski

Here is the link for the cost Azure Blob Storage pricing

Consider you have multiple tiers so you can configure you your storage account under Lifecycle management to move from one tier to another base or creation or modified date (ex. from Hot to Archive)

For performance it will depends on multiple things , especially on the connectivity between your on-prem site and the Azure Region where you do the backups. Also I do recommend to try it yourself to get a better picture . Make sure you compress the sql backup as well as split to multiple files

Regards

Javier